I recently played a multiclassed Transmuter/Barb/Rogue that had Ghostform. The spell was great for recon and scouting, but not so good once the fighting started. Granted, the Wizard was more martial than most, able to hold his own with a short sword and a nasty bowman with Greater Magic Weaponed and Bane Weaponed arrows, but many of his spells were also unusable while in Ghostform. Thus his combat capability was practically reduced to Magic Missiles; I couldnt even use most of his buff spells becuase they were creature touched. Thus, I typically let the spell drop once combat started.
Ghostform is still a really good spell, though. I dont agree that it should be 7th level, however. While some Wizards are going to be less affected by its drawbacks than others, it still blanket removes a number of spells and options and limits the Wizards AC as well. If you get hit twice as often, 50% miss works out the same. Many foes faced at 9th level and up should have some way of counteracting incorporeal. 5th level seems right to me.
My favorite 5th level spell is Shadow Evocation; I love the flexibility of the spell and the higher save DC. Its backfired once or twice thanx to lucky saves and vs a couple of opponents who looked like Fighters but turned out to have levels as Clerics (and thus had high Will saves), but its worked many many many times to my best advantage as I was able to take advantage of current circumstances when choosing which spell to mimic.
Teleport is a great and powerful spell, but it can also be very disruptive, slow down the game, and make life very hard on the DM. Thus, while its a great spell when it expedites progress, its not so great when it halts all forward progress.
