I'm not really sure why there aren't better games out there yet. Certainly one problem I've had with Android that I suspect would be better with iOS is the limited amount of memory that I have to work with on Android. Android doesn't give you all the available memory to work with, so it's an adventure to make a 2d game (bitmaps with a transparency layer get big fast). This might explain part of the delay on better games.
I think better games are coming, but I can't really explain why they're not already here.