Did you not take Adroit Hands or Vitality Boost? 5 maxed buff/attack skills means you didn't pick up something else; unless those all have unusually low requirements. Plus, you maxed Mental Absorb. As a Wizard, I never ever found it worthwhile.
At 99 I took 3 levels into vitality boost and 5 into nutritionist. I wasn't really getting hit much, and I have a bangle from the amazon's LoC that regens health per hit.
I don't need adroit hands, the sorc's spells are all about crowd control, there's no need to stack any of her spells (there's no slow + blaze equivalent for example). I only cast spells to get the mobs out of the way when I fight a boss, otherwise there's really no need for spells.
In other news, just cleared LoC 9-1 solo, and got a broom that boosts all spells by 50%. AWESOME.