So, I have a few games on my iPod Touch, and to be honest, they are alright. But the thing with iOS games, is that they all really end up being repetitive. And thus, become boring after a while. Some games you actually play through without it feeling repetitive, but apart from that, the games get boring very easily.
My opinion on this, is that some developers need to actually spend a bit of money, and perhaps make a multiplayer game, that you can play a lot without it getting boring. It should also have customisation and unlocks, to keep the player interested, in wanting to unlock the new items or gear, but obviously the unlocks shouldn't give too much of an advantage.
I believe that this would increase the iOS gaming market, and give some incentive to actually buy games that have over 100+ hours of re-playable value.
This would also expand the iOS market to new developers, who would want to be able to get a game out there, that people would enjoy, and that the developers could actually push continual updates out, adding new things, and premium items to support the developer(s) hosting everything.
I think this would have a kind of Call of Duty effect, how there would be the main game that lots of people play, and buy the new one in the series. It lacks a good campaign, but makes up for it with lots of multiplayer time. Personally, CoD isn't my cup of tea, but I do know that people spend a lot of time playing online on it. I believe that if there was a game that could provide the same sort of feel as CoD (And by that, I mean replayable-in-multiplayer value) the iOS market would be a lot more profitable.
I have sent in a few ideas like this to a development studio, who make apps for people if they believe that they would be able to make a profit out of, but sadly they declined. I don't mind though, as I could probably find someone else who would think this a good idea.