I'm just blown away that you can do that on something that weight about 10 pounds (probably significantly less in the next gen.). It's true you need great gameplay that keeps you engaged to have a great game, but that just looks amazing. There really is almost no limit to what you can do now on an iPad. I mean based on that you could literally play World of Warcraft on an iPad (those graphics technically look beyond WoW).
One thing I think can be a liability is the lack of physical buttons or joysticks, for some game genres (like this one). I never end up liking virtual joystick type games on iOS, that interface always seems clunky and unnatural to me (although there are things that are equally clunky doing on physical joysticks, like gestures). The other is mobile devices with cellular connections still have more latency than home ethernet/WiFi connections, making it difficult to do multiplayer action games well, especially those that are server-based.