They don't have to give precise formulas. FFXI had some complicated ass formulas, as any of us FFXI-ers will tell ya fast. A basic idea would be nice (more so for DD classes and tank class imo). If it's something like SS in FFXI was, for instance, it could be as vague as "Absorbs damage based on MND." or SS2 "Absorbs an increased amount of damage based on MND". While that's not the only thing it's based on, it would still give non-FFXI-ers a freakin clue. lol.

I think this is more important for DD abilities. "Damage is x% based on STR, decreasing in value for non-lancer/doW classes" or w/e.