Would it be that much hard work to fit it into the bestiary ?
I do think it'd be worth doing. Consider: at the moment BRP doesn't have a bestiary, now it's highly unlikely that having published this one that Chaosium are going to do another with with hit locations, strike ranks etc etc just for BRP vanilla. Which means that by default this is pretty much going to be the BRP bestiary. Now consider the idea of hit locations, they are very popular. I think all the Alephtar Games supplements use them. All three Chaosium BRP settings (Trollslayer, Chronicles of Future Earth, Mythic Iceland ) use them. All of the monograph's I own use them. They may be an option but for all practical intents and purposes they are the default setting for BRP supplements. So if this is going to be the only BRP bestiary then it'd be a real wasted opportunity not to put them in. Not only would it appeal to those who use Magic World ( and lets be honest here it does sound like the supplements are going to be pretty damn good ) but It'd reach to a wider BRP audience as well.