Ok, a few things here:
1. I love seeing backstage and behind-the-scenes stuff too (I worked as a stagehand for 4 years in college), and I have taken Backstage Magic and Keys to the Kingdom tours, but I DO NOT want to see it when I'm On Stage. They are two worlds, and I want to keep them separated. It is indeed a bummer when you're riding the MKRR and you see the tunnel from the main lot to the parking lot behind TL and Main Street, and the parade driveway, and the overpass that brings the CMs to the main tunnel entrance.
2. Exit Signs: I am a Construction Manager, and have had the "pleasure" of reading the International Building Code. You have to understand that every ride, show or attraction is FIRST a building, then an amusement. In ANY building, you have to be able to clearly see the path of safe egress from anywhere in a public corridor or areaway. These signs must be lit at all times, because the power won't necessarily be out when there is an emergency. The emergency lights come on only in a power outtage. I agree, it's a bummer to see bright red signs when you're floating along in your log, or traveling through a dark ride, but they're required by law - and there for OUR safety. The last thing I want is to be stuck inside the maze of Splash Mountain and a fire break out - and not have any idea how to get out of the warehouse - bad news!
3. Take a look down the canal, west of the MK, when you're on the monorail the next time. You can see ALL the way back to the locks, and see the electrical pageant barges as well as the Parade Storage Facility. Bad show.
4. Eat at Cinderella's Royal Table, in the castle, and sit by the windows. You can clearly see the new Wishes Fantasyland launch points, on the rooves of the neighboring buildings.
5. As for the backstage walk to Fantasmic, I just think of MGM as one giant "backstage" park. That's why they don't have many certain areas where CMs have to walk - their costumes are appropriate anywhere in the park, since they're ON and "OFF" stage there.
6. I've never had a ride or attraction ruined for me, just by seeing it with the lights on, because I know its not real to begin with. However, when I can see roads, and cars, and the sides or tops of warehouses when I'm engrossed with my surroundings in a park, that's when it loses some magic. I bring up the train ride again - I LOVE trains and i LOVE riding MK's, but I only want to see roads, and cooling towers and water pipes and parking lots when I'm on a tour or driving to the park.