I know I'm gonna be in a minority here, but that's fine. I was definitely a little disappointed when they revealed that it was a card game, because the logo and name definitely evoked "Destiny-alike" to me. But, thinking about it, I'm probably more excited about this than I would be any other Valve release aside from perhaps Team Fortress 3 or an actual fresh IP. I don't have a ton of investment in their other franchises except for Portal, which doesn't really need another game at this point.
From the little Day talked about it, it sounds pretty different structurally from most of the other card games out there right now, so I'm eager to see it in action. Maybe (like HearthStone did for me with Warcraft) it'll give people who don't want to deal with MOBAs a way to get invested in the Dota 2 universe.