The Staff of Aesculapius’s base type should be changed to a staff of healing. Ironically, this would mostly affect non-healers using it, since healers already get expert in healing spells, but it’s more flavorful to be this rather than a quarterstaff.

It should be possible to forge spell staves, possibly by combining a quarterstaff with multiple spellbooks of the appropriate school. The only problem is this is not very flavorful with a red-hot forge, which might suggest that there should be some alternate crafting method that can be used to create them.

A way to permanently mount a spell staff on a square. This makes it unremovable but it permanently provides its casting benefits to you while you are standing on that square, without having to wield it.

Spell staves should remove a much greater share of armor penalties for spells of their associated school than they currently do.

Another possible bonus they could have to make them more worthwhile is to treat any spell of their associated school as cast at one higher skill level than your current skill in it (does nothing if you are already Expert, since defining Master effects for spells is likely out of scope).

Using a spell staff allows you to cast spells of the associated school while not necessarily being able to speak (due to polyform or some other reason); it could also potentially suppress other impediments to spellcasting, such as confusion.

An enchanted spell stave will boost your spellcasting in its school, with a greater boost the higher the enchantment is.

Spell staves are made into poor melee weapons (comparable or worse than the club, being basically a stick that’s just sturdy enough not to break), but are made lighter than the quarterstaff, weighing only 10. Its bonus to a single spellcasting school is countered by it applying a slight spellcasting penalty to spells of some or all other schools.