I will go on record and say that I do NOT believe Voyager weakened the Borg. It was always more a matter of overkill than weakening them in my regard anyway. The Borg were not meant to appear all the time on TV Trek, they were meant to be used a certain way and that way became forever altered by the time the feature film First Contact came along and introduced the Queen and, indeed, more horrific ways to assimilate people that contradicted earlier stories and suggested ideas. Voyager simply took the ball and ran with it with having them on all the time from about mid-way through the series' seven year run. As stated elsewhere I actually enjoy Endgame even though it was the last TV Borg story in 2001 (Until ENT did their own episode but thats for another discussion) and featured their apparent final end, not counting the endless books that have been brought out since that time.