Restore ability potions can (partially?) cure amnesia effects.

Track the highest-reached enchantment of enchantable weapons and armor. If it gets cancelled or disenchanted below this peak amount, you can dip it in a potion of restore ability to immediately raise it back to that peak.

The potion of restore ability can be used to recover lost maximum Pw. It only restores maximum Pw, not current: if your Pw is 30/80 and you previously had 100 maximum Pw, these potions will only be able to get you to 30/100.

• If cursed: does nothing (as usual)
• If uncursed: you recover one quarter the difference between your current maximum and your peak maximum, or 5 points, whichever is greater.
• If blessed: you recover half the difference between your current maximum and your peak maximum, or 10 points, whichever is greater.

Make the potion of restore ability alchemizable somehow. Possibly with something non-straightforward but making use of junk potions, like healing + sickness.

If you are only getting one attribute restored from a potion of restore ability, it selects the one that is the most points below its former maximum, rather than picking randomly. Or else you just get to pick the stat you are restoring.

Dipping a spellbook in any healing potion will restore one of its read charges. Dipping it in a potion of restore ability will restore all of its read charges. In either case, the potion is used up.

Rename the potion of restore ability to “potion of restore attribute”.

Remove restore ability vapors healing monsters to max HP, because that makes no sense.

Restore ability (potion or spell) also cures wounded legs, “restoring your ability” to jump, kick, carry, etc, and will cure most status ailments as well.

Cancelled monsters can quaff potions of restore ability to uncancel themselves.

Give potions more side dipping effects:

• Dipping an eroded item in a healing potion repairs erosion on it; 1 level for regular healing, 2 for extra healing, and 3 for full healing. Restore ability will repair all erosion as well.
• Dipping a negatively enchanted item in a restore ability potion reverts it to +0 if the potion is blessed, adds 1 point if uncursed, and does nothing if cursed.
• Dipping an enchantable item in a gain ability potion enchants it (by 1 point, always).
• Dipping an uncharged item (possibly excluding rings) into restore ability has the same effect as uncursed charging it. (Blessed charging cannot be reproduced this way, even if the potion is blessed).