good guy, you need to enhance your writing.
Don't think BOS would make good villains, they're a relatively small organization and rarely interfere in the affairs of the wasteland, not to mention that by 2220s they're not as aggressive as they become later on.
I think BOS should be ultra-rare in AoP and a single BOS paladin should be able to fight a party of 6-10 players all by himself, and a paladin squad should be able to challenge a ZC squad with the best gear. Remember HELIOS One? 1:20 disadvantage, NCR loses thousands of soldiers, BOS loses 50-100 because they're in a bad defensive position against a immense horde of enemies.
A splinter faction of the BOS, especially one with access to large hordes of cannon fodder somehow (robots? clones?), on the other hand...