I guess my feelings about sight lines is that if you can see other attractions, that's one thing. Especially if it's iconic Disney attractions, (like the Chinese Theater or the old Mickey-ears water tower). If it takes away from the "atmosphere" of where you are, if at all possible, it should be somehow disguised (like the backside of TOT being able to be seen from Epcot, but looking like part of Morocco). The bigger issue would be if you could see back stage stuff, or unsightly things like big garbage dumpsters.... that would not be cool.