Almost every coaster at WDW is in a warehouse. You just can't see it because they give it a decently themed facia on the side that faces guests.In trons case it's so close to Space Mountain that they could've incorporated the same style of design and cover up the fact that it's a square metal box.
In GoTG they could've taken the approach they did with Soarin and have a comdination of it being lower down to the ground, and add a burm in the park that to a guest just looks like a grass covered hill with trees. Would it cover it completely? Absolutely not, but its a darn sight better than big grey boxes everywhere. Even RnR at HS looks better and in that instance you genuinely do stare directly at a big warehouse as you walk into its outdoor plaza.
It's not a question of it not being possible, it's just money and lack of care.