BAB means the Fighters hit better than the Wizards, period.
I am thinking of a spell....
It begins with W and ends with raithstrike.
If AC is useless then Wraithstrike is useless. In fact, every spell giving a bonus to attack rolls is useless unless it boosts BAB as well, because BAB = Power Attack = Damage. Wizards only get one of those, and it takes away their Spellcasting. Therefore, if AC is useless then BAB means the Fighters hit better than the Wizards, period.
Also, anything True Seeing can do, Mindsight can do better. Mindsight is easily attainable through any one of a battery of dips/grafts/spells + 1 feat, and completely negates invisibility, displacement, mirror image, and arguably half of blink.