The only guys that have failed really bad for Bill were Gowin, Ryan Young, Wiley, Mitchell, and Rivera.
Outside of Rivera, none of these guys were a considerable cap hit. Mitchell got hurt. Gowin got hurt, but proved to never be that good anyway after he left. Rivera has been hurt as well and I don't think it's out of the realm of possibility for him to play pretty good next season...if he's healthy. Young was playing well until he got injured and had to retire.
The other FA's like Anthony Thomas, Vinny, etc. were just one year deals. Not much was expected from them and they didn't get much in return.
Other than that, Parcells has gotten some good play from Bledsoe, Anderson, Keyshawn, Terry Glenn, Campbell, Ferguson, Singleton, Henry, Aaron Glenn, etc.
The important thing is that none of these FA's have truly crippled them or put a big dent in the salary cap. And outside of Wiley and the 1 year deal guys, injuries had a lot to do with their disappointing production.
Rich........