My other question is, do you think it's okay for the PCs to learn them via training from other adventurers for MONEY?! (Obviously not the templates, but like, the technique granting feats.) As in, the PCs run into a trio of ToB-ers, they pal around for a bit, and the Cleric goes "Hey Crusader, I really like that one thing you did, with the killing people. Could you teach me?" And the Crusader goes "Why certainly my friend! But these services don't come cheap, as we're also a group of greedy bastages an adventuring party, so I'll have to charge you X."
There are items that emulate some of the feats so I think there's no big harm if you get the feat version for the same price.