I'm not a fan of the Soarin' showbuilding being visible from inside the park, but I think there is an ever-so-slight distinction between Soarin and the various showbuildings at IOA.
With Soarin', I'm sure the bulk of Guests who do see it have no clue what exactly it is. The building itself is so separated from The Land (and you can't really see it when you're anywhere near The Land) that it just seems to be some backstage building that they tried to hide.
With Potter, Poseidon's Fury, etc at IOA, you have a highly-themed section of the exterior, and then it suddenly stops and becomes plain showbuilding. The attachment of the two is clearly visible, lessening the impact of the themed portion.
Of course Disney is guilty of this same "mistake": Parts of Mansion's building visible above the exit, the Main Street buildings ending and being visible just beyond the Plaza Restaurant, the upcoming Dumbo queue building (though I'll wait for final judgement on that until it's done and all the landscaping has been added), to a lesser extent the Mexico showbuilding as visible from Test Track.
-Rob