This is just how the Eagle's offense works, which is why I always target McNabb and not their receivers in the draft. Since they do spread the ball around, it is very difficult for one WR or TE to put up elite numbers for an entire season. Certain teams take certain players out of games, and then the Eagle's go to another player to pick up the slack. I do think, however, that by the end of the year LJ will be one of the top TE. He is still a top 3 option for them in the passing game.
As for the play calling change, I don't think it is as big of a factor as many think. Yes, Marty "officially" called all the plays the last game, but he had already been making about 50% of the calls the entire season. All of the offensive coaches work on the game plan, and I'm sure Reid still has plenty of input into the team's strategy. When any of the players are asked about it, they really don't see it as a big change, and Reid has done this many times in the past with other coaches when his offense is struggling. I actually think the biggest change will be their continuing tendency to go to the no huddle, which seems to really limit the defense's ability to matchup with all the Eagle's weapons. Although it makes it harder on their defense, the opposing defense has difficulty substituting and implementing their game plan due to the quick snaps.