Yeah the only real plus I could see to putting it outside would be if you made it part of a fully assembled set with the boosters and fuel tanks but then you couldn't see all the little details that I personally love from seeing it up close and knowing this thing that's 10 feet from me went to space. You could put a replica up if you were doing the fully assembled version and get just as big an impact because the flaws in the replica would be hidden by distance.
They have an iron bird on srbs and an et on pedestals at SpaceCamp in Huntsville. This is the only reasonable way to display an orbiter outdoors: use a scrap one. The remaining flown orbiters should be preserved indoors, obviously.
