Those are a whole bunch of changes you listed there.
So what you're saying is, we're not close.
I think that Miami was close under Sparano; all they needed was a few guys on offense to help get into the endzone, and the coaching/playcalling on offense was poor.
The defense always (or mostly, anyway) kept them in games, even against superior opponents. Miami was one of the few teams who could consistently slow down Brady. The problem has always been scoring TDs. Under Sparano, Henne and the running game usually had no problem marching down the field; they could move the ball. It was in the red zone that they always fell apart due to no superior playmakers, bad playcalling, and Marshall dropping too many TDs. Under Philbin the team did better in the red zone, but made it there too few times. Every defense knew that Miami's o-line couldn't block in Philbin's scheme, so stalled drives were commonplace. Philbin even said when he was hired that in his system, the short passing game will basically take the place of the running game. With no true FB and a lack of emphasis on running the ball (and possibly a blocking scheme that didn't fit the players), Miami was terrible at converting 3rd and short and keeping the ball away from the opponent.
IMO, it's easier to improve the team that can get to the red zone than to fix a team that can't convert a 3rd and inches given two tries!