Thanks, glad you like it.
As to the D8, there a couple of reasons.
Opens up basic Gish Options. Blasty Arcane Strike Gish is an Option, etc.
My Fixed Sorcerer has a D6. Only Fixed base class with a D4 is the Wizard.
This is meant to be part of my line of fixes, which includes my Minir Magic Fix. Caster take NonLethal damage equal To the Spell Level.
Granted, even without my Minir Magic Fix this increased Hit Dice is not imbalancing and will certainly offer a different feel making it a viable option. The guy was Tier 4, I simply bumped him up to Low Tier 3.
Edit: One other Point, a Druid has a D8...
Edit2: As always I invite anyone to check out my other class fixes and my 3.5 Overhaul located in my Signature.