It's partially the graphics, but it's predominantly the gameplay. The old RE games and mgs1 both control terribly which is confounded further by a rubbish camera. No matter how important other aspects are, such as plot etc, you play a game. There is very little satisfying about controlling a tank (when it's not supposed to be one).
Backtracking is the most offensive thing to me along with other padding such as fetch quests. Code Veronica and wind waker are extremely offensive in these regards respectively to the point it almost spoils the entire game.
There is a weird amount of love for first games in a series. I recently played through all tr god of war games and 3 is easily the best in terms of gameplay. Everything is better, yet it's the first that gets the most praise...! The mind boggles. Granted, 1 did have the best plot but the fighting was the tightest in 3.