Do any of you think Hearthstone could/would add expansions from their other IPs? Maybe even adding 'classes' from Diablo and Starcraft; I'm sure this has been discussed before. Not saying it better happen soon, or even in the next few years, there's still plenty of WoW to pull from.
If they do I bet it will be several years yet and even then I think its doubtful. They have built a good thematic feel for hearthstone and you have to be really careful about messing that up. Sometimes it can spice up the game but often it just makes everything feel fake and will drive some people off.
Well, as was already pointed out, the name of the game is called Hearthstone: Heroes of Warcraft. So, just adding a card directly from another game, like a Tyrael legendary, will probably never happen. They may however bring in gimmicky crossover cards; something like Grunty (the murloc marine non-combat pet in WoW) or something along those lines.
I highly, highly doubt it. Other than some small Easter eggs, it probably (and hopefully) won't. If they want to add Starcraft characters they can make a starcraft version that is an independent game. The game is called Hearthstone: Heroes of Warcraft.
You guys have a point with the sub-title Heroes of Warcraft, but it does seem a bit tacked on, everyone just calls it Hearthstone. Like it could easily change to Hearthstone: Angels and Demons; or Hearthstone: Zerg Rush, etc.
But if it never happens, you won't see me crying, I'm hardly a Blizzard follower.
Warcraft is already a messy dish sink of various lore ranging from victorian horror, tolkien, lovecraft, steam punk etc. They can throw in sci-fi and my little ponies and all that other crap for all i care, since its already screwed up a long time ago.
Seeing as we can't even get monks or death knights, classes from other IPs seems extremely doubtful... but you'd need that in order for those IPs to have a proper presence. So yeah, not happening. Or you could check every single dev interview where the question has come up and they answered the same.