If only one of the two classes had metamagic, I'd have to go with Sorcerer. A Wizard learns an exact set of actions needed to trigger a magical effect, which doesn't leave a lot of room for experimentation, but a Sorcerer KNOWS magic. He should be able to do far more with one spell than a Wizard can, since he should inherently know how to alter it.
If anything, I'd say have Wizard bonus feats only be used for item creation and Sorcerers get corresponding bonus Feats to be used for metamagic. At first level they'd get Eschew Materials, but only if you allow the house rule that Sorcerers can use their known slots for metamagicked spells to get around the increased casting time. That way, every spell they know has it built in. Convenient, huh?
But then they're too similar. I've been trying to come up with some way to combine the classes, and here's what I've got so far:
MAGE (Mag) (well, actually, I commonly call them Sorcerers, but I wanted to get back to the old days)
> Spell list is Sorcerer's, including any level changes you'd make by using the alt.Sorcerer list, i.e., Shield at 2, Haste at 4, Mass Haste at 7, etc.
> Spells are spontaneously cast like a Sorcerer, including the increased casting time for metamagic
> Spells/Day and Spells Known are as a Sorcerer.
> Skill list is Sorcerer, plus pick two class skills from the following list: Knowledge (any one), Speak Language, or any of the CHA-based non-exclusive skills (Diplomacy, Bluff, Intimidate, etc.)
> Bonus Feats: Eschew Materials at 1, any other metamagic Feats at 5, 10, 15, and 20
> Save DC is set by CHA (the ability to force your will on other people)
> Bonus spells are determined by INT and are added to spells KNOWN, not spells/day. Only permanent INT (innate, inherent) helps for this; a Headband of Intellect doesn't give you extra spells.
> Need INT of 10+spell level to know a spell. Headband works fine for this.
> Need CHA of 10+spell level to CAST a spell (this one might get removed)
> If they want to get around the metamagic time, they can take the Prepare Spell feat to act like a PHB Wizard.
> This is the magic of Chaos, so no Lawful characters can take the class. (This ties it to Bards better) Likewise, Psionics is the magic of Order, so no Chaotic types can take Psion.
> Gnomes have this as their new favored class; the three free cantrips are simply added to their spells known and don't count against the maximum (and non-Sorcerers get one use per day of each)
> Elves have Psion as their favored class.
Making them be 2-stat casters instead of 1-stat makes a huge difference in power, ESPECIALLY when those two stats are INT and CHA.
Anyway, it's just a concept, any comments?