[Icelander]

Any game I play will have a plethora of schools, regional or personal variations of the base styles in MA. There will also usually be new several styles not in MA.

If a player asks 'can I learn a version of style X that includes Y', I will generally allow it if there is some way such a variation makes sense in the campaign. Note that 'my sensei was a pretty wacky guy and taught an extremely unorthodox personal interpretation of X-fu' is generally valid and makes sense for a wide variety of campaign worlds.

I'd only refuse if I didn't allow trait Y in the campaign, demanded prerequisites that style X could't give or if I felt that the request was purely metagame and sacrificed setting integrity for mechanical utility.

Given that taking martial arts styles at all is of questionable mechanical utility, there is no attempt to balance styles against each other and even Perk-heavy styles are hardly overpowered with an extra Perk, I don't worry much about abuse.