Hearthpwn

I feel like he's going to have a different effect each class like how his adeventure fight is going to be 

Quote from Zerosha >>

Quote from Sheena314 >>

I don't want him to be a card that people want to auto-include in every deck. That seems uninspired to me

 I disrespectfully disagree. A card-to-build-around should be really exceptional and original in it's design, archetype-defining even, not just a good card. 

I think he would be really cool as a Neutral Hero card: you could make yourself one of the unique Deathknights, or you could become the Lich King. I don't know how that would work in a way that would be balanced for all nine classes, but that could be an interesting thing to play around.

Otherwise, I want him to be a force to be reckoned with on the board. A major threat with significant combat stats, as opposed to a gimmick for combos or some other effect.

They should make him like Nefarian and give him loads of voice lines for different opponents.

"I want him to be Dr. Boom + Patches-level of auto-include. I want him to be so over-used that people will sigh when the turn of his mana cost begins, because they know exactly what sort of BS to expect."

No.

I want him to be unique, above all. If I see another C'Thun/Jade style of deck I might break my jaw from yawning so much. I want him to be unexpected, doing something new, even if it sucks ass as a mechanic. Surprise me WITHOUT breaking the game. That's what I'd like.

Quote from linkblade91 >>

I think he would be really cool as a Neutral Hero card

I'm guessing he has synergy with the hero cards. The death knights themselves are meant to be the old gods, deck defining legendaries of the expansion.

Yes, i want it to be a build-around card, we don't need more neutral high rarity staples that every deck has, much less a legendary neutral staple,  that's bad for the health of the game, Look at pokemon with god damned Tapu-Lele Gx, basically if you don't own Tapu lele-gx you can insta concede in tcgo whenever you see the psychic-type symbol showing in your opponent's deck during the loading screen.

Did someone say he's five mana? In that case, I'd like him to have some kind of effect that works with the 2, 3 and 4 mana neutral legendary prince cards that currently look useless - something like 'if Prince Keleseth, Prince Taldaram and Prince Valanar are all active in your deck and your deck has no 5-cost cards then DO SOMETHING FRICKIN' AMAZING'. That would be a build-around and no mistake...