@OP: People have explained why this wouldn't work. a few more things of note
Casters are already MAD due to needing con (d4HD is a joke) and dex (limited AC, ranged touch attacks, bad BAB).
Also, making them MAD would not in any way balance them with martials because the issue is spells not attributes
Also, consider that a +2 ability item is 4000gp (4th level), +4 is 16kgp (7th level), +6 is 36kgp (9th level), a caster can start off with 8s in all scores. He will be very underpowered fighter until level4-ish when he gets level 1 spells and cantrips (+2 item +1 levelup), at level 7 he would have 3rd level spells and be able to cast the +4 ability score spell to get access to 4th level ones. 9th level he is fully caught up and no longer has limit on his spells. He never really needed the bonus spells per day and the low DCs just mean he should use a "save:no" spells.
I swear that's the most overhyped spell. DC 10 balance or you can't move. Oh noes, I guess all those enemies with ranged attacks/teleports/flying/natural high dex/ranks in balance are utterly at the caster's mercy now!
what are you talking about?
http://www.d20srd.org/srd/spells/grease.htmThe target must make a reflex save or fall prone.
Standing up provokes an AoO, prone characters cannot shoot, prone characters have difficulty casting, prone characters have difficulty attacking, and prone characters must spend an action to stand up, and they take -4 penalty to AC vs melee (and +4 bonus vs ranged)
If the target starts its round on the grease they must roll again or fall again.
If the target successfully saved against falling then they can either stand still for the rest of the turn, or try to move, if they try to move they must roll a DC10 balance check to move at half speed, a failure by 5 or more means they fall, a failure by less than 5 means they must roll a reflex save or fall
Also, it can be cast on an enemy weapon to disarm them or on yourself to give yourself a +10 to grapple and escape artist. That +10 is nothing to sneeze at, you can easily beat most opponent by grappling them... or ever better, at mid levels cast grease and silence on the fighter and have him grapple the BBEG
Most DMs would let you set it of fire or get creative with it too (grease the lock, etc).
PS. I swear I remember it stating that if the target is standing on an incline or running across a smooth surface they auto fall without a save but the SRD doesn't mention that...