Even now it is harder than before, you already need quite some good quality to impress the users.Sometimes the idea and gameplay really pays !
Like some games where simple cartoon style (so no shader based game) are greatly and cleverly used with addictive gameplay !
OMG pirates Sometimes,polished graphics, with addictive gameplay and big replay value makes it :
Infinity Blade I played it it's simply addictive you want to re make the fight boss lot of times until ypu collect top notch equipment !
The gameplay is combat only,and just choose branching path ,but it works !
Angry Birds it's just physic gameplay addictive that asks you to think how to win a stage !
Guerilla Bob was also simple and great cartoon graphics but
addictive and fun (i just would have liked more vast levels
on the sides, and more diversified levels) !
Guerilla Bob Well just wanted to point that only good ideas or polished
points on a game will make it work indeed !
The big point is selling and distribution that in AppleStore
really simplifies all, caus you don't have the problem
to find or thrust a publisher !