The controls are a little more complex because they added some systems to the game that didn't exist in GTA. The only complaint I had about GTA 4 was the driving was not tight at all, other than that, it wasn't as bad as you are making it out to be.
That is what I was talking about with GTA 4. That and I think the auto-aiming system was kind of borked in GTA 4. They fixed it for GTA 5. But my main complaint with the controls in this game are the horse riding. First, I think it's a little jerky which causes some out of the blue crashes. Second, I find it odd that I have to tap on a button multiple times to get my horse to slow down. Third, like I said, a horse is a sentient being, it should be able to avoid some obstacles on it's own. It should never run face first into a tree when you make a blind turn.