Awesome set! I saw this set on Hearthcards and I would like to congrats for finish such a huge project, and with relative balance to boot! 

Overall thought: The change to keyword a mechanic that has been in the game for a while is very much appreciated since this is one of those things that should have been done in the beginning.  However, it would be very challenging to design Overpower without Rush or Charge since the mechanic is inherently very slow in HS and the game has an oodle of removal and clear to counteract the lack of interaction. The focus on card type is a very interesting idea in both the short term in Standard (as they can push the Location and Weapon printed to have more usage then they otherwise would have) and long term as they can open the door for these cards to have longevity in Wild as stronger Weapon and Locations being added and can tutor them out. The flavor of the set might be repetitive from Rashtakhan's Rumble, but that was a very underpowered set so another attempt at the excellent is always appreciated.

Thought on inidividual sets, on a scale of 10 from both balance and design:

• Death Knight: Design: Oh boy. More Rainbow DK support. These should be fun with Necrotic Climatic Explosion in Wild. Libbiara seems extremely annoying, with her Ice Block lite effect that not only can heal but slam the enemy board, which can end the game to aggro decks. Her Rune status is completely justified because she would be completely broken in 3 Blood DK. Balance: However, Sword Instructor seem extremely overpower and limiting to card design. Foam Render give this an easy 5 Ghouls that can slam into the enemy and create Corpses for the class. I think this card should either be 6 mana or has a much smaller body like a 3/2 or even 3/1, or a combination of both like being 5 mana and 3/1. Overall score: 8/10 on balance, 9/10 on design. Favorite card: Runic Cutter, a great fusion of the craft weapon mechanic, Rainbow power and the mechanic focus of each class.
• Demon Hunter: Design: An attempt to give DH more late game oriented strategy is always appreciated. And these cards seem to be more practical than the extremely underpower big Demon DH package that we have been given in the past. Well Done! Claw Coach Aranna run into the problem with low cost hero card - if you draw her early she can completely taken over the game with the force attack, but if you draw her late she is completely useless. I think she should cost higher (like 6 mana) along with a more impactful Battlecry. Balance: Combatant Manager seems a little above the curve. We saw a 2 mana 2/2 that draw a card in DH before and it has to be nerfed to a 2/1. While this effect can go off only one time, the stats buff is way more to make up for it. And unlike the other card, this card get extremely better in the late game, with the potential to give way more than a +1/+1 buff. For that reason I think it should be down to either a 2/1 or a 1/2. Champion Bodybuilder has way too many stats for such a dangerous effect. 8 Attack is too much that if you ran this against a token deck you can pretty much OTK them if you can summon him out, something which is possible with large Demon cheating and discount the class has received in the past. I think he should be a 6/14 to reduce his lethality and increase his Taunt potential. Design: 9/10, Balance 7/10.  Favorite card: Bolderon the Unbreakable, what a powerful and unique effect befitting of a boss monster of a new archetype.
• Druid: Design: Bringing back this theme is a stroke of genius. The Un'Goro set itself never did anything too interesting with it, however the actual design of some of the cards leave something to be designed. Brawl'gar Beastiary: I really don't like bleeding design space from another class like this. Discovering from another class is supposed to be Priest and Rogue thing, with maybe Mage in certain sets if the situation called for it. Quackenbush: Another potentially degenerate combo cards. This can do rediculous things with minions with strong effect and high cost, not only getting them out with less mana but also having more copies of them, something like Owlonius Druid would salivate for another chance to get their combo piece. Balance: Intimidating Stance seems to cost a little too little. With 2 mana you can snowball the early game really hard, especially if you get lucky with the token and get some strong effect like Rush or Poisonous. I would make it 3 mana with a +3/+3 buff. Design: 6/10, Balance: 8/10. Favorite card: Basins of Renewal, a powerful and interesting infusion of the set's mechanic with the Druid central mechanic.
• Hunter: Now this is a great design space. This allow for a more spell oriented Hunter to shine, something of a personal favorite as well as a not very common idea in general. Design: Nothing to noted here. All of these are excellent! Balance: Archery Instructor is super overpower. Not only is it a tutor for a class without much card draw to begin with, it can deal A LOT of damage, especially if the board is empty because you didn't specify two of those targets have to be different, so if the board is empty it can deal 8-12 damage face easily. It also limit future design space for weapon. Johnny Awesome: The +2 Spell Damage on a decent body is nut! I know there used to be +2 Damage on much worse body on non-Legendary and it was used just for that, and the couple that with the Overpower bonus turned your removal to direct damage. I would give it a 1 mana nerf. Design: 10/10, Balance: 8/10. Favorite card: Grizzly Grapple: A solid defensive card desperately needed for the archetype and Hunter in general.
• Mage: It is always dangerous to give Mage more damage, but their position as a class has been week until pretty recently, so more expansive lethality would push them into a more aggressive tempo focus direction, which is something I have always liked. Design: Nothing to note. Everything is excellent and fitting for the class. Balance: Memorabilia Fanatic seems a little too weak. Its effect isn't that strong given that you can't control what you get. I would lower it to 6 mana. Design: 10/10. Balance: 9.5/10 after the update. Favorite Card: Large Fireball. Interesting and unique spin on this kind of mechanic.
• Paladin: Give Paladin more weapon is something I have always noted to be rare, so a set like this explore that is always very welcome. Design: Nothing to note here, standard midrange in flavor stuffs for Paladin, but Ahoo'ru might need a small text to explain to the user what does "Triple Divine Shield" means. Balance: Black Market Handler might give too many stat, with a total of +10/+10 in buff that you can access extremely rapidly, especially couple with the fact that it has a solid body and that you can have Divine Shield minions. I think give only +2/+1 or +1/+2 buff and maybe reducing the body to a 4 mana 4/5 would be suffice. Design: 10/10, Balance 9/10. Favorite card: Weighted Walloper: A hilarious and interesting card that allow you to balance between value and tempo.
• Priest: What is this? A resurrect effect that is not completely overbearing? Well done. Allow for more tempo and midrange playstyle without being obnoxious is hard to do so I salute you for it. Design: Nothing to note here, excellent design. Balance: Dominika seems weak, especially for a Legendary. Her board can be blow away by a stiff breeze from any control deck, something which I imagine the deck that contain her would have trouble with if they ever fall behind. Maybe lower her cost to 7 mana? Design: 10/10, Balance: 9.5/10. Favorite card: On-site Hospital: Powerful card with effect that allow for great mind game and decision making.
• Rogue:  MORE COINS, MORE COINS. I have always have a soft spot for coin generating in Rogue. So this set is especially dear to my heart. Design: Right-Hand Ruffian seems to be lopsided in the power distribution in the Discover effect since 90% of the time Coin will be the choice, which kind of defeat the purpose of the card. Maybe if you can give the discount to the card you Discover by (1) then the other options would be more attractive? Balance: Match fixing seem very overpower as a 1 mana kill any minion. The only class that has that kind of efficient removal is Priest with the Light It Burns, a class with much less proactive early game and even then it is still much more conditional than this card. I would increase its cost to 2 and increase the damage to 3. Design: 9/10, Balance; 9/10. Favorite card: Underground Gambling, allows for powerful turn but with a caveat of skipping the rest of your turn. An interesting balance between tempo and combo potential.
• Shaman: The Shaman's quirk, some would say versatility and some would say lack of identity, is utilized very well here as a multi spell schools, rainbow class. Design: Nothing to critique here. Everything is well thought out and fit with the theme. Balance: Hydro Hammer is way overpower. Running this with the Nature damage spells package and you scale this to 10 or 16 extra damage pretty easily with some miniscule set up. I would lower the Spell Damage value of this to +1. Design 10/10. Balance 9/10. Favorite Card: Tidemistress Shellbreaker, a powerful value generator that actually reward instead of punish you for casting every single spell schools during the course of the game.
• Warlock: A unique take on Zoolock. I can tell there is alot of effort to put into how you can benefit from flooding the board instead of just putting more stat onto the board. Design & Balance: Ferocious Fiend Club violate the design space of not giving Warlock many direct damage. Yeah you are encourage to use on minion but the fact that it is as base a Fireball is insane - A card that is so powerful in Mage that it was brought back to the core set without any buff. This should be nerfed to only be able to target minions. Design: 9/10 and Balance 9/10.  Favorite card: Fel Blazer, what a clever way to benefit from big board. This allow for direct damage but you have to build and sacrifice your board to it.
• Warrior: Now this is what proper Arena brawl theme set should feel like. Top to bottom flavor is out of this world and on point. Good job.  Design: Nothing to say. Everything is solid and flavorful. Balance: Axe Instructors: Once again, like the other two Instructors, way overpower and limiting the design, especially in a class known for having big attack weapons. Buffing the board isn't never really in flavor for Warrior anyway, so I would recommend either remove the board buff or increase its cost to 5 with a weaker body. Black Market Smith also deal a little too much damage to ease of which to use. I would nerf the damage to 2, increase the cost to 6 or nerf the body to 3/2. Design: 10/10. Balance: 7/10. Favorite card: Brasscutted Bleeder. Putting this condition into a weapon immediately raise the skill cap needed. Do you play it now and overwrite your existing weapon for 4 damage? or do you prefer to play it at the end so you can get the full value.
• Neutral: All of the Neutral are on theme and offered interesting niche and design space. Well done! Favorite card: Fitness Room. Simple. flavorful and oozing with potential. Operated Junkbot: In a set with very aggressive themes and mechanic, it is nice to be offered some reprieve tech cards that can serve in midrange and control decks. Design: 10/10, Balance: 10/10.
• Miniset: How does board clear interact with Hexos? If it work like how I think it is then the card is even more overpower than I thought (spell only work half the board?) Even if board clear work normally, Hexos is still extremely overpower. Just plop it in a Agrro or Midrange deck without any thought (because it doesn't require a deck building or play condition) you get a severe leg up to the token decks and any slower decks that attempt to use Taunt minions to reduce the damage. Bloodshredder seem cost a little too little for something with insane synergy with the rest of the set. It might need a nerf to 3 mana. Edit: Arcane Vollier seems a little too good for her cost. 4 mana 5/6 and +3 Spell Damage might be a little too efficient. I would nerf her main body to only have +1 Spell Damage. The rest of the mini set is well designed and balanced, but this one singular card Hexos would make the entire meta worse because of easy to use it is, so I have to give Design 8/10 and Balance a 5/10 if Haxos affect board clear and a 7/10 if Hexos doesn't affect board clear. Edit: Favorite Card: Dagger Instructor - one of the more balanced Instructor. She reward Rogue to actually put weapons in ther deck. Rogue isn't famous for having high attack weapons, so she should be fine.

I reread it and it is true. If it puts it your hand then she is fine then. But the point system for the miniset still stand because this singular card will warp the meta to reduce the value of Taunt minions and tokens deck, both of which you seems to print cards for this expansion. Especially slaps on a card with no deckbuilding cost and an above the curve body