Hm. Thinking about it... a Fighter/Wizard could easily have an AC of 25 base (14 Dex + Mage Armor + Alter Self (Troglodyte) gets AC 22, before equipment). Greater Mighty Whallop will cause a blunt weapon to deal damage as if it were two size categories larger; for a heavy flail, that's 3d8 damge. Wraithstrike (a second level spell) allows all attacks in one round to be treated as touch attacks. Attack bonus, if a Fighter1/Wizard4/Abjuant Champion4 would be BAB +6/+1, with say +5 from strength, +2 from Greater Magic Weapon, and perhaps a +2 from misc sources such as buffs, abilities, or feats to get a +15/+10 total. There's no extra attack, you can power attack with a 2 handed blunt weapon and gain *1.5 strength mod to damage,. So, two attacks at 3d8+2+7 each come out to an average of 45 damage. Three attacks at 4d8 each come out to 54 damage each.
If the gish power attacks for 2 points, he deals 53 damage on average.
Hurling things can be done with Telekinesis, stunning people can be handled by a variety of spells such as Hold Person... you could probably duplicate all force powers with D&D spells.
As I said in the first post, probably not worse for balance than a well build gish.