We will have a more balanced offense in terms of how the ball is spread around. The OP forgets to mention that the Tight End position was still a productive position before Shockey and Graham as we had Campbell (blocking TE) and Billy Miller (Recieving) who helped pave the way for Duece and Reggie (Campbell) and exploit linebackers in coverage (Billy Miller) and I think we will see simular production from the pair of Tightends we have today in Watson and Hill.
I think the biggest concern is on both sides of the ball and thats with the younger playes who are being thrust into prominent roles or are expected to contribute early in their careers we should expect some highs and lows.