Back Lot Tour, at the time it ended, went through areas that are now occupied both by TSL and SWL. TSL took over not only space that was occupied by BLT but also space that was actual back stage where there were no attractions at all.
Between TSL and SWL what was lost was:
- an already shuttered Back Lot Tour
- the car stunt show
- a playground
- a flex theater
A new flex theater was built (Sunset Theater). And 4 new rides will have been added, 2 of them E-Tickets. And 2 new 'lands' to replace the 'land' of Back Streets of America. So, DHS's footprint expanded with the back stage areas taken over by TSL and Sunset Theater (not to mention all the new parking and the SW Resort).
WRT Pandora: An unbuilt pad is an unbuilt pad and will be unbuilt forever until they build. Once they do build, that should be considered a park expansion. The new Fantasyland expansion was considered an expansion and not "well, they just built on the land they were supposed to the whole time!!" Adding more footprint to the park is expansion and the dismissal of such is the point of view of those who don't want to give Disney any credit for anything.
In that regard, TRON is extending the footprint of MK. Don't know anyone saying "well, that's a pad that should have been built up all along so, I won't count it as an expansion!"
Similarly, UoE is being replaced by a new ride, and so, it's easy to think of this as just a one for one trade off. Except that the new ride has added a giant plot and expanded the footprint of UoE, and thus, expanded the footprint of Epcot. Think of it this way, they *could* have put the Guardians coaster in UoE and taken over WoL as its queue. But they didn't. They went beyond the parks boundaries and expanded the park's footprint.
The park's in-use-for-guests footprint will expand some more for Ratatouille, Brazil, and Poppins.