Losing pally Prestige Enhancement III is a big lose. KotC gives very good DPS and DoS gives about 4 extra AC, as well as other benefits.

The sorc lvl quickly becomes obsolete when you have full ranks into UMD, since you'll be able to use scrolls, wand, and all that stuff sorc lvl granted to you but, well, without the sorc lvl.

The extra SP won't matter much, because with SP you'll either do 2 things:

A) Cast extended battle buffs, like prayer, favor & zeal, or resistances. In this case, rest with an archmage item, buff up with resistances, cast 1st wave of battle buffs and switch to your correct item. You'll still have about ~20 mins of battle buffs with the remaining 200 sp, and that is usually enough.

B) Self-heal. You'll still have to grind your ears to make it worthwhile, because you won't be able to replenish your mana fast enough, and believe me, +200 sp won't make much of a difference when you jump into a pack of orthons and intimidate them.