there may be situational AP enchants that don't work
having done some disposable BG levelers the following AP enchants from northrend work
boots - assault
bracer - assault
gloves - greater assault
you can test AP enchants by looking at a attack like arcane shot damage before the enchant and after
i put gloves - greater assault +2 AP on a set of gloves it made my arcane shot bump to 101 dmg on a level 12 player, as my enchanting increased i put gloves - superior agility +2 agi to the same gloves and my arcane shot dmg is still 101
enchants have changed from expac to expac and sometimes on a patch, PPMs, dmg, heals, broken for over a decade then all of a sudden work, and classes that could not use some enchants since van wow are useable now like LS for feral/guardian druids, enh shams