The platform is as 'casual' as you make it. They don't only play Angry Birds, you know? In depth and hardcore games also get releases on the platform and seem to do pretty well - I've played FFIV and FFT on mine, as well as stuff like Bastion, XCom, Baldur's Gate, KOTOR and more games than I can even remember at this point. So to me as a player this is great, they're releasing these games on my RPG/adventure platform of choice.
'Hardcore' gamers need to get this idea that phones=casual out of their head because it's outdated bullshit, and it shows you up as not knowing what you're talking about. For these kinds of games a touch interface works very well indeed, and the portability of having it with you at all times is a massive bonus.