Here is the problem though. It's not an eye sore. It's a closet on the side of a building. Most people wouldn't even notice that there was something there if they didn't know about it.
It's not a huge area that's closed, as far as let's say if they closed Big thunder, splash (rip), 20 leagues (rip).
If they put something there, it can't be a huge attraction there isn't the space.
And in the age of social media, you won't get the constant, here's the latest building update photos, or the aerial photos of the area. All of that is free advertising for Disney. Outside of Disney leaking photos of the progress inside the show building, the fervor that is built online would be mild. You dont have 100 youtubers that every day walk by to show you the progress, and give out that free publicity and build the excitement.
So in their mind they want to build stuff that people are excited about during the 10 year build process it takes them. A small attraction that will be hard to really promote until its almost opened, doesn't get the same buzz that something like Tron, Star Wars, or Tiana has.
Now if they had a great idea that could live in a small footprint, fits tomorrowland and could be done cheaply, it might get greenlit, but the parameters arent that exciting compared to a huge blank canvas or an area with no creative limitations.
Sadly that's the world we live in, and that's the way the people in charge think. In my opinion.