it would be 15 ap + a food buff (the one i have used was 5 str for DK but i am p sure there is better.) Some consumables are useable, like health potions and the BG potions, havnt tried everything yet but its p much as you said nothing that is really abusable Tried crystal of insanity already, will try the fel-core one when i get to it but i dont think it will work.
idk if warrior is a great example bc how powerful the crusader proc is at this lvl. Also, your point is entirely valid from a stats bulk perspective sync is terrible, you will never be ass strong as a vet, not even close really.
You do, however as a warrior get an interupt and heroic leap, those are nothing to scoff at (and again, still not even close to worth losing crusader enchant.) A sync character is about as strong as a pure FTP, a little less stat bulk but more skills is more skills.