That bad thing about diving is that its too successful for players wanting to stop it. THerefore diving will always be in the game unless its inforced some way.
As for video replay I dunno if i'm for it and I really dont' think it will ever happen.
I'd like to see electronic offsides though. Have some sort of computer system pick up the ball and the Defense to offensive players and beep if the ball is offside. I'm sure it can be done without question.