The Staff Magus seems like a meaningless archtype. The main selling point of the magus, the ability to crit with spells, doesn't synergize at all with the quarterstaff's x2 crit.
Actually, let's just take a look at what you get:
- ability to use the staff one-handed.
- ability to use the staff normally, which prevents casting
- earlier Weapon Specialization: Quarterstaff
- Shield bonus to AC using the staff's enhancement bonus.
- Staves are treated as quarterstaffs at level 10.
- Ability to recharge staves at a pretty high cost.
No one is going to use the staff as a double weapon if they want to cast. Using a quarterstaff anyway is a terrible idea. The weapon specialization is nice, but nothing mind-blowing. The shield bonus is the only real positive I can see about the thing. As for the enchanced staves, well, you're still better off getting a real quarterstaff and enhancing it.
Now, here is what you give up:
- Weapon proficiencies, and heavy and medium armor proficiencies. Nasty, but the Quarterstaff Defense makes up for it, somewhat.
- FIGHTER TRAINING. Say goodbye to GWF and GWS.
- Ability to reliably hit with crit spells, aka most of your damage.
Conclusion: You nerf your damage output, in multiple ways, for some slightly higher defense.
I think this needs a fix. Here's my idea:
Staff Casting
A Staff Magus can use the Quarterstaff as a double weapon or use a two-handed grip, but is still able to cast spells. The Magus can also enhance both ends of his staff as a single swift action.Less spell damage for more weapon damage. Besides, the image of a guy in robes beating a dragon to death with a big stick is freaking hilarious.
Staff Flexibility
At first level, the Magus can use the quarterstaff as a one-handed weapon. As a swift action, the magus can adjust his grip on the staff (which doesn't provoke) to treat it as a reach weapon, or to shift it back. This is the SM's main shtick, having reach with melee touch attacks.
Weapon and Armor Proficiency
The Magus is proficient with light armor and doesn't have the arcane spell failure chance while wearing it. This replaces the normal armor and weapon proficiencies of the Magus. Less defense for offense.
Staff Defense
At 7th level, the Magus gains a dodge bonus to his AC equal to his staff's enhancement bonus. This replaces his normal armor proficiencies. This is supposed to represent parrying with the staff, which is why it's a dodge bonus. Apparently, magic is magnetic, and like deflects like.
Staff Channel
The Magus can channel his ranged touch attack through his staff, adding the staff's enhancement bonus to his attack roll. Come on, you see wizards channel spells through their staffs all the time in literature and other stuff.