I'm no fan of the Speedway. Never have been. Never will be. And while I get that kids still like to drive their own miniature cars, I think that's something that can be better integrated into EPCOT as a second Test Track attraction or the Studios in Pixar Place with a Cars theme. Not just because driving cars doesn't fit thematically into a Tomorrowland, but also because the attraction sits on such a large piece of land with so much potential.
I also think the Speedway is part of the problem with the Fantasyland/Tomorrowland transition. Right now, the northeastern spoke of the hub tries to be an entry into both lands, whereas every other spoke devotes itself thematically to just one. And I'd venture to guess that it's because the Speedway reaches as far north as it does (remembering, of course, that before Mickey's Birthdayland, it wended its way even farther north).
If the Speedway were removed and just the northernmost sliver of the land it currently sits on were turned over to Fantasyland (whether as a mini-Wonderland, a Storybook Circus expansion, or some other solution), that northeastern spoke could finally be dedicated to just Fantasyland instead of the half-and-half solution that's in place right now. I just don't see a reason that you should be looking at Tomorrowland architecture while enjoying a cup of coffee at the Cheshire Cafe.