IMO, frontline fighters without a decent Fortitude save suck. Reflex saves just save you a few hp, which a frontliner should have buckets of anyway. Fortitude saves do nasty things to you if you fail: Poison, Disease, Stunning fist. There is more, but these three things are common enough for frontliners to run into that Fortitude is required (IMNSHO) by all frontliner base classes. Because lets face it, a Str-poisoned fighter is basically useless, all of a sudden he can barely move, nevermind fight.