TT 3.0 will be the least abstract of the three iterations. I'm expecting show scenes, larger and more immersive sets, a greater sense of space (greater use of the space too), and linear story on-board narration ala Spaceship Earth. (I'd love it if the narration was a radio station with music and a "host"...I'd expect an instrumental version of "Fun to be Free")
Going back to my earlier post about Chevrolet rebranding their messaging... Chevy introduced the tagline "Find New Roads" in late 2012/2013. TT sponsorship switched to from GM to Chevrolet and TT 2.0 opened late 2012. The whole sim track/Tron/design your car/electric car theme fit well with "Find New Roads" and fit well into the Epcot theme at the time. Synergy baby!
With Chevrolet now shifting brand messaging to "Together let's drive," TT 3.0 will get a story that will fit VERY well into the new human-connection themes of Epcot. It's no longer about how technology changes our world, but rather how it changes us and our place in that evolving world.
WoM was the former. It dabbled in the subject of our personal connection to transportation (mostly showing archetypes), but it was really more focused on the changes in technology and how that alone changed the world around us.
A Spaceship Earth refurb will likely follow the same new themes, moving away from communication technology itself and more toward what we communicate and how our storytelling has evolved with new tools.
I think they'll (Chevy and Disney) want to connect us to our love of driving throughout the generations and how that gets passed down, then show why/how/where we drive today, and finally bring us to the open road of the future generations. It'll likely be a much more emotional and optimistic story.
Not everything in Epcot perfectly fits with these themes but keep it in mind when evaluating any new rides or refurbs we may get in the future.