I've always liked tomorrowland, and future world in Epcot. Unfortunately, I think without Walt's (or really anyone's) continuously changing vision, it will only become more outdated and laughable. Sticking with Tomorrowland, I think Buzz Lightyear needs to be cleaned up for starters. Compared to the comparable Toy Story ride in HS, it's much dingier and less appealing. I think some paint could go a long way for starters, and I think they could also work on the lasers. It seems like there's always a couple out of commission.
Not sure why the laugh floor is even in Tomorrowland. I think it would be better suited for HS but whatever. I think that there should be more warning to first timers that people from the audience get selected to participate/have jokes made at their expense. I think if there was a designated area (like a splash zone at water shows) where people want to be chosen that would be better. (Unless people are informed ahead of time, and I was just unaware of that)
I love the TTA. Some of the "future" components should probably be updated. They show things like video chat, which was very sci-fi futuristic upon its inception, but very commonplace now.
Speedway can get out. Unless they can switch to solar powered or electric little cars, there is nothing futuristic about this.
As far as coming up with ideas, unfortunately I'm no imagineer. I don't know where the line is between Epcot and Tomorrowland, but I would like to see more of an emphasis on global unity and peace, promoting respect and tolerance for other cultures, researching energy sources, etc. Overall, encouraging people to ask questions about the world around them and inspiring them to want to learn and create.