Driver 4 is at least an improvement on Driver 3.
Addmitidly some aspects have been improved like the character system, with the player having a wider range of character controls than just shoot and walk. Like wise the graphics have been improved even if the improvement is only just visible and the ammount of vehicles for use is wider. However the ability to swim and use boats has been removed and replaced by the character commenting on how he hates swimming.
But on the other hand the game does allow a multi-era experience which I have enjoyed considering some of the other let downs in the game.
All in all Driver 4 is a game that can be played for a while but those annoying little things can put you off after about 2 hours.