Well if you just look at it by position, the Bills have a legitimate starters at WR1, WR3, TE, RB1, RB2, FB, LT, LG, C, RG, RT, DE1, DT1, DT 2, CB1, FS, P, LS, KR. That is if the major FA are resigned. There could obviously be improvements to some of those spots, but for the most part those guys could start in multiple cities around the NFL and do at least a solid job. That leaves QB (2-3 spots), WR2, DE2, OLBx2, MLB, SS, CB2, CB3.
That's really 10 holes, which is a lot. But there are guys at those positions that could potentially get better or fill the hole while we pay attention to other positions.
Guys at those positions that I think are capable of becoming good players or filling the hole: Nigel Bradham at OLB, Da'Norris Searcy at SS, Mark Anderson at DE2 and one of our young guys should be able to shape into a third/nickel corner.
That leaves six needs to make a move on this offseason, along with depth/injury replacements.