It's called "evolution". The park will eventually have to break construction standards to accommodate for new attractions whether or not those standards fall in place and make an attraction blend into the scenery. For example, take a look at Tower of Terror at Hollywood Studios - the reason why it's designed the way it is so that it blends in with the architecture of Morocco at Epcot. If the construction standards did not call for such a design to be built like that, is that going to deter from your experience because ToT is designed differently than Morocco's architecture?
And, here's another question for you - how are you even worried about sight lines when you're at ground level anyways? You're going to be able to see what's in front of you anyways - not what's behind another attraction. So, if I'm walking around Frontierland at MK towards Splash Mountain and turn around - I don't think I'm going to see the "undisguised warehouse on the edge of the park" in Tomorrowland and don't even go there with the "view from atop Splash Mountain" because when I'm at the top of Splash, the only thing I care about is that drop. The buildings in the distance? Don't care.
Tomorrowland needs another thrill ride anyways to help with the wait times at Space Mountain. Tomorrowland has been in a state of status quo since the mid 90s. I mean, other than the removal of Alien Encounter (which was more of a thrill show than a ride), it would be cool to see Tomorrowland get a refresh/update for MK's 50th Anniversary. I know I'm pretty excited about Tron.