[Bette]

The passing game was not their strength in 2007 with 2842 yards between J.P. Losman and Trent Edwards.
Bills kept their top receivers and added James Hardy as another passing option.
The highlight of the year was the emergence of Marshawn Lynch. Here's hoping his off season troubles remain in the off season. The Bills were 15th in rushing but only had 20 TDs. Hardy is expected to give them the boost in the red zone that they need. If they can resolve the contract issues of LT Jason Peters and get him on the field, there should be a solid OL to run behind.
The defense was not spectacular. They need to get more pressure on quarterbacks. Teams gained too many rushing yards and had to much time to pass. The linebacking corps should be upgraded with the return of Paul Posluszny from injury and the signing of FA Kwika Mitchel. The secondary was the weakest part of the defense, but it should get a boost with the signing of first round pick Leodis McKelvin.
The Bills have a reasonable schedule and the level of their success will depend on the growth of Trent Edwards.

Buffalo Bills—a Look to 2008 | Bleacher Report

Will the Bills be better this year?

[Lefty Noob]

So many issues do deal with. Will Lynch be available? Will Peter get signed? If the answer to those questions is yes, then the answer to the question of "Will the Bill be better this year?" will be yes as well. But obviously you can't lose key players in the running game like these two and hope to compete, especially with a wonky passing game.