Everyone else is wanting to munchkin up then. As written it is only a block on breathing. Well, and possibly scratching an itch underneath it.
I really don't have an issue with blocking breathing doing one resistible stress per round. Thematically, it's sound and arguably mechanically sound since spells are allowed to block things other than movement and damage, like perception, sight, etc... The breathing thing sounds like it should be a rarely used side rule like falling but they didn't expect it to come up often enough to bother.
Personally, I don't allow truly universal blocks or grapples because I've yet to hear an argument for one that can block a non-spoken spell being cast by non-mental means other than running water or those annoying shackles. Also, I'm not that particular on how a block is described but I do require that it be described and I don't let fire-and-forget evocation do complete grapples (ones with all the grapple aspects) at all because it's outside their scope.