I'm sure they can still find reasons to corporealize. In fact, lets throw a few of those reclaimed ranks into Use Magic Device, since it gets nice synergy bonuses from other skills, but can't use it untrained.
Updated. Do we want to revise the spell list to account for the metamagic feats?
Yeah, it is. I like the spell list except magic jar. How about we keep Reach Spell, give it a reach vampiric touch at 5th-level, and swap out Repeat Spell and Silent Spell with Spell Focus (enchantment) and Greater Spell Focus (enchantment)?
I can go for most of that. I'd still like to replace magic jar, though. It just feels like a "cheesy" attempt to become more a full ghost (since it lacks malevolence). I'd rather it strive to be a bit more distinct, than strive to be similar. <shrug>
Updated.
Time to figure out CR. A ghost is +2. The wizard actually loses several spellcasting levels. Is that enough to offset the gained abilities, giving it a CR adjustment of +0?
A ghost has a LA of +5. I could see reducing it to +2, since 3 spellcasting levels are lost. Or maybe +3, due to the better manifestation than a standard ghost.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.