I so agree, with both of your statements. Walt meant for the Monorail to be exteded to all the parks, providing transportation to anywhere in the resort property. Unfortunately, Disney decided not to continue the Monorail any further past EPCOT, since it was tremendously expensive to build. I wish that they would take the extra expense and extend the monorail that far since riding the monorail is very convenient, and doesn't take as long! I love the monorail...
Anyhow, that would be the BEST QUALITY of change for the parking lot to be removed. I don't think that will happen, though, since it costs over $1M per mile of monorail track.... (not saying that Disney doesn't have the money, but oh well.) It is more likely that if Disney wanted to expand Hollywood Studios, and they had to get rid of the lot, they would expand the lot of the close Blizzard Beach Waterpark (across the road), and repurpose the the land there (from a conservation site, which it may be) to more lot space and possibly an area where transportation will be used to transport the guests across the road to the park. In any case, the monorail seems like the simpler plan...