Greetings there! I'm here to present you my version of how I would change Mage's Core Sets. I'm jumping the bandwagon a bit with the changes after seeing some other people trying their reworks and generally accepting classes may need some updates.
This time, I've put crossfire onto Demon Hunter. This one is different, becuase DH doesn't have a Classic Set yet, but this will be a fun opportunity to theorycraft a potential one for the new class. Keep in mind that this change also includes an overhaul to their Hero Power, making it costing (2), but giving +1 more Attack on each version. It's more to streamline the class, to not confuse new players and to get a new perspective on the balance.

Strengths and Weaknesses
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- Strengths
- Weapons - Demon Hunters have a plethora of weapons to attack you with.
- Card Draw - Demon Hunters track you fast.
- Aggression - Your health is in danger.
- Hand Manipulation - Insight helps you control the resources you use.
- Demons - These hunted monsters are also your allies.
- Limitations
- Minion Swarms - Demon Hunters usually prefer larger minions and not mere pawns.
- Survivability - Demon Hunters can sustain during a fight.
- Weaknesses
- Card Generation - Demon Hunters rely on their instinct instead of outside help.
- Non-Attack Burst - Demon Hunters beat you consistently instead of in a one fell swoop, and they prefer slashing through everyone.
New Sets
Explanations
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Battle Felguard - an aggressive minion to complement Demon Hunter's fast and furious, slash and hack playstyle.
Aeladori Prophet - gives the class an access to manipulate their hand to benefit the most from Outcast effects.
Warglaives of Azzinoth - changed from the unbalanced state to a more soft board control tool.
Demonic Sigil - adds an evergreen Demon buff to Demon Hunter. Aside from giving a buff, it can also let the target attack twice.
Skull of Gul'dan - changed from reducing the cost of cards drawn to reducing the cost of itself.
Dark Portal - while it is card generation, it is more akin to Warlock by giving you Demons and not other cards. It's also not really a card generator, because you replace cards in your deck instead of shuffling some into it.
Illidari Dancer - the ultimate attack buffer.
Cordana Felsong - she's a warden in WoW lore, and so she provides some defensive capabilities to the class.
Hall of Fame
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Well, just one card, but that is because Glaivebound Adept is already in the basic set, so it can be HoF'd.
Some cards that were considered, but didn't make the cut
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Felosophy - well, card generation, but it would've probably been a fair one.
Demon Companion - this was meant to be a Basic card due to simplicity and similarity to Animal Companion, but I forgot it was a dual class card.
Cycle of Hatred - big AoE and summons, but maybe it was a little too good.
Double Jump - was meant to give Demon Hunter an evergreen way to trigger Outcast more consistently, but tutors are dangerous in general, and Prophet probably does the job better.
Blur - wouldn't mind seeing in the set.
Ancient Void Hound - was thinking of trying to change it to be a defensive feaster, but maybe it was not worth the effort.
Vilefiend Trainer - lacked room
Priestess of Fury - also lacked room.
Among many, many, MANY other cards…
https://youtu.be/3-bwJzmuDX4