Hunter and Rogue seemed to always have a Poison synergy but never really explored it. I thought that maybe something like this would be outrageous with cards like Pufferfist or Blademaster Samuro but seeing that these weren't really played in tandem with cards like Plague Scientist often and that the deckbuilding cost is a bit steep for this hero card, I thought it'd be fine.

Rezan is the Loa of Kings, a being so mighty that all lesser kings (i.e.: random Legendary minions) leap to his defence. Rezan's Hero Power, King's Bite, unleashes the power of his fearsome jaws; do you use it to keep your opponent in check turn by turn, or do you build it up over several for one almighty finisher?

Given Rastakhan's Rumble's thematic focus on loa, I was surprised when Rezan, pre-eminent among them, didn't make an appearance. A very cool character to turn into a custom card, and the combined foci of Taunt minions and attacking with your hero made Druid/Warrior a natural fit. 

In the lore Anduin becomes King of Stormwind and succeeds his father Varian Wrynn, even taking up the legendary weapon Shalamayne. This card combines the love of healing, health and Holy spells both paladin and priest share. By gaining more max hp on your hero you can better utilize healing and lifesteal cards. The weapon you can swing for 3 heal on the spot or use the spell synergy for a stronger heal against large enemy boards.

'Choose Both - Tree surgeon; or cosmetic surgeon.'

"How much liters of blood will you sacrifice for power? Three? Two? One? Nihil?...NIHIIIILL!!!"

It's Tess Greymane, only focused more on her being a member of The Uncrowned (a secret shadow organization of rogues).

Her Battlecry can be used to Sap an enemy minion or Shadowstep one of your own. With the Combo, you can mix-and-match: two Saps, bounce two friendlies, or one of each! The Hero Power mixes together two Secrets that share a trigger: for example, if you pick Dirty Tricks in your initial Discover, you can combine it with Cat Trick or Pressure Plate. The card would release with more Secrets, obviously, to round out the options.

Shout out to a particular individual for reminding me that Tess was a Hunter/Rogue combination in Monster Hunt.

Rogue and Shaman both have some Battlecry support, and both classes like to use them. Mistweaver Sha'keth opens up countless different possible combo routes to explore with its Battlecry-chaining ability.

An example of how this might play out:

A pretty cheap Hero card that makes use of several mechanics usually associated with both Druid and Warrior, such as Armor, Hero attack, Taunt and Rush. It also uses two exclusive mechanics in Cleave (usually used by Warrior) and Choose One.

The Hero Power is well suited for tempo decks, but slower decks can also make use of it, as both Rush and Taunt are pretty effective defensive tools.

Finally, Druid can use it with Linecracker, BEEEES!!!, Earthen Scales, [Hearthstone Card (Soulbond Ashtongue) Not Found] and Silas Darkmoon for a pretty obscene OTK, but I don't believe it would be too problematic, as it requires many different cards and a lot of Mana too.