I have no desire for more walls.... BUT, their new layout of the hub would potentially allow them to methodically take down a quarter of the hub one section at a time and implement fixes.
Pipe dream of ideas would be to remove rust elements (including the funky trees, walls, etc), tweaking the landscaping design (there's some areas right now with some very thin bushes and a s**t ton of mulch that just doesn't look great), obviously and maybe most difficultly, a clean sweep on lighting design (and control system if needed...). Would also love a stronger barrier (dense trees? idk) between seating areas and the backside of the Communicore DJ booth if they're continuing on with that monstrosity of an entertainment choice.
As for the center, a revised planter maybe that's not as bulbous/ginormous and something that a landscaping team can actually be creative with and make it a proper statement. And lastly, complete gut redo of Epcot logo in-ground lighting. I still like the logo concept, but you could pull off the same design and use fiber optics that pulse to the SSE light shows instead?
Final pipe dream would be a proper new fountain farther south right at the edge of the bldgs, but that's like 100x more of a stretch than my other hopes (which are probably already unrealistic)