Rav said:
The thing is that there is parity between the classes with belts of Giant Strength and headbands of intellect, and Spell Focus and Weapon focus and Specialization.
Greater spell focus, introduced in a splat book, suddenly broke the parity, without introducing something on the other end of the spectrum.
Okay, lets talk about parity. We have been assuming that a Wizards DC's are roughly equivalent to a Fighters Attack bonus in terms of being combat-effective, so I'll go on that.
Fighter's Strength affects BAB and Damage, Wizards Intelligence affects DC. So far, so good.
Both Fighters and Wizards can increase their Strength and Intelligence through Magical Items, Wishes, and the every-four-levels Stat Boosts, so again we are even.
Fighters have Weapon Focus and Weapon specialization to increase both their attack bonus and damage, and wizards have Spell Focus to increase their DC's in one school. I'd say we are still even on this score.
Now, according to you, it's GSF that breaks this chain of parity, but allow me to inject some other things into the equation...
Fighters Attack bonus and damage can increase with magical weapons. Wizards have no equivalent DC booster.
Fighters Attack bonus can increase with certain buff spells and effects (not including the Bull's Strength or Endurance type spells as they are subsumed by magical stat boosting items). Aid, Bless, Bard's Inspire Courage, Belsameth's Blessing, and Polymorph Other just to name a few. Wizards have one DC boosting spell that I know of (spell enhancer) but it's only good for one single spell, whereas the other examples last for several rounds or minutes or even days at a time. Fighter wins out here, bigtime.
Finally, Fighters get better Attack bonuses
as a function of their level . Every time you level up, you get a +1 to your BAB. Wizards have no such equivalent booster to their DC's.
To top it all off, whenever a fighter gets a +1 Attack bonus, it's good for
every attack he makes. Spell Focus and GSF only enhance one single school, which will likely constitute only a portion of a Wizards spells. So, taking all this into consideration, I am in no way convinced (nor will I likely ever be) that Greater Spell Focus is unbalanced or makes Wizards the Ultimate Bootylicious Butt-Kicking class.