Oh, in general, sorcerer is MUCH better than warmage.
All the warmage can do is do mean things to people. While they're VERY good at that, they can't do anything else useful. The DM in my al-Qadim game expanded the skill list so I could at least do something out of combat, but for utility spells, I ain't got nothing. Had the shugenja/hakima not D-Doored me out last session, I'd be dragon-chow.
However, if you have items to cover deficiencies, or other casters to carry that role and warriors to hide behind, the warmage can rock the house. My character has 8 spell levels, but casts at 10th due to Practiced Spellcaster, and with his Int of 20 (16, +4 Enh.) and Improved Edge, his average Magic Missile damage is equal to or higher than a regular Sorc's Maximized one. I can also choose freely between what spells I have, so I don't have to worry about not having Acid Orb on my spell list if I have to fight a troll. Since you wear armor, you don't necessarily get tagged as a spellcaster by an opponent (until they see you cast, but that means that you might be free the first round of combat).
It isn't what I'd consider an ideal caster for a party, but it's quite nice. I chose to play one for sheer simplicity.
Brad