Ummm, maybe not. A major advantage of the 3-4 has nothing to do with Xs and Os: you increase your odds of drafting a really good player who's either too small or too big for his position in a 4-3. There are an awful lot of NFL teams running a 3-4 defense now so, as long as most college programs play the 4-3, the Bills are better off sticking with the 4-3 because they'll have more options when rebuilding through the draft.
I think the biggest problem with the Bills defense is not the alignment but the scheme; the Tampa 2 is an anti-pass scheme better suited for warm, passing-friendly weather. Given that they've only ever had one penetrating defensive lineman, Schobel, it's no wonder that they can't get off the field on third-and-long.