The only reason I brought in the Ferrengi is because they would be the most likely to help the Borg organize some sort of cult, if it were profitable, and not worry about things like the Borg increasing their numbers until they could once again try and assimilate all intelligent life. On the other hand, the Dominion might work better. The Ferrengi might just get themselves exterminated.
I agree that defeating the Borg shouldn't have been so easy, but we have to start with what went before, and only a few scattered ships being left. Or do we?