IV's terrible replay value and annoying A.I. for starters. The small map, the concentration on more realistic gameplay after a game like San Andreas, the poor graphics for the PS3/360 gen, and low number of weapons, cheats, clothes, and customablity.
I thought the controls were fine.
Terrible replay value? Considering it has such a good story and an amazing atmosphere, It's great to replay.
I don't see how AI could be annoying at all, apart from friend calls. Everyone complains that the AI in GTA V is annoying with peds calling cops on you for nothing.
Compared to III and VC, the map isn't small.
The realism made vehicles so much more fun to drive.
Graphics aren't poor.
And it was the first game on a new console.
But they did spend too much time on useless things, the TV commercials, the internet websites full of useless details, look at that nice machete in the commercials that you can't use, or the Red Buffalo billboard yet the only available one is a Black FIB variant!
Besides, GTA V doesn't have many cheats either.
The story was terrible. The early missions suck.
The AI sucked because it sucked. The peds, police, friend system, gangs, and other drivers.
The map is small compared to SA, which is ridiculous because they had a lot more memory and spent all that time developing Rage. It doesn't matter if it was their first for PS3. They delivered a half-baked game. The graphics could've been A LOT better. They were awful in retrospect, especially when compared to GTA V. Like I said: half-baked.
...GTA V has more cheats than IV. The invincibility cheat makes up for a lot!