I also ran across issues with the current incarnation of Filter Extensions, but A) I concur with FreeThinker, that's something for the FEx folks and B) It would appear simply deleting Filter Extensions outright doesn't seem to have done any harm thus far in my campaign (and restores all the old categories), and KSPI still has its own tab if you really need it :>
My question probably ought to be, for clarification as to whether I dun goofed with my aforementioned actions, is Filter Extensions vital, or rather, will my not having it do anything untoward? o: