Hey,
"but perhaps not as big us you'd think.",
I know what difference it makes and for what jobs, I agree not all make a big influence but some do like Buffalo Bill's Soft Leg Guards and William Tilghman's Pistol Belt. Those 2 make a big difference for some of the hardest jobs there are.
"Since the "All Jobs" build, is not really all the jobs, but just most of them"
Is that a fact ? (I dont know). After the update when you do the Animal Spirit quests, you will have another 12 Attribute Points.
I have (almost) all possible store buyable items (just finishing the last ones), all best items for all jobs. I am level 120 so have the max amount of SP and AP from that, and currently 3/4 Animal Spirits quests finished.
I am wondering if there does exist an "All job" build with these AP included, atm Im not so sure there is not.
Edit : With Crafting items I think an All Jobs build is possible, with the Gentleman's Dinner that includes 60 LP on all jobs.