won me over. Hearthstone is a very different game from Magic, despite some obvious similarities. I want Hearthstone to remain a very different game. Even as wildly successful as Hearthstone has been, however, Magic and other card games have some great ideas that I think Blizzard should borrow to make their own game even better.
1. Format variants
Magic has many fun variants, most of them multiplayer: free-for-all, Commander, Two-Headed Giant, Star (or Color Wheel), Planechase, etc. Some of these were invented by players and later adopted and supported by Wizards of the Coast. One of the joys of Magic is how flexible its formats can be.
Compared to that, the single format of one-on-one battles in Hearthstone is less exciting. (Of course, Hearthstone is limited by its technology in a way that real cards aren't.) Sure, we're getting a raid in Curse of Naxxramas, which could shape up to be a fantastic single-player variant. But an online game like Hearthstone, with millions of available players, begs for multiplayer formats. They could be competitive or cooperative, playing against other teams or "bosses."
A Planechase variant could be adapted quite easily by using the different game boards, once Blizzard adds a few more. Multiplayer variants will be more tricky due to the game's current layout, but I have faith that the developers can make it work.