I think extending the skyliner to DAK was part of the initial plan of the project, but it got canned because of COVID. It may eventually be resurrected. I'm just not convinced it's going to fly over office space and parking decks. Yeah the backstage areas of EPCOT are pretty bad I agree. I also think that making DHS a pass-through stop like Riviera could be a major issue and lead to huge bottlenecks.
Staying at Riviera, I often have to wait for 4 or 5 gondolas to pass before one has space for my family to get on - and let's be honest, Riviera is a fairly small resort all things considered. Imagine that at the busy DHS stop, with gondolas passing by that are full from DAK and Coronado guests. It would make the Skyliner so much less convenient with long waits to get a gondola, even at off-peak times.
And God forbid they tie in the All-Stars. They would have to rebuild the entire project into an omnimover to have a hope of it having enough capacity.