Tron is very much shine over substance. It'll be a huge hit on social media and casuals will love it, but it's over so quickly that it's ultimately less satisfying to me. You don't get the longer ride time that you would on any of the mountains or Incredicoaster.
RE accessibility: I think it's more of an issue that it's just a weird car to get into if you've never done it before. It's not something like Big Thunder or Space where you sit down quickly, pull down the lap bar, and go-you need to KNOW how to manuever to get into the vehicle to an extent (it's a little similar to Pony Express at Knott's).
I fit on Tron in Shanghai when I was around 300 pounds, and my much-bigger friend did Flight of Passage at DAK with no issue, which has very VERY similar restraints. So while there will be issues, I think some of them will disappear with time as the CMs get more comfortable with how to get guests into vehicles and guests become more comfortable themselves with the boarding process. This leads me to believe that while it's never going to be a ride that fits every guests, it can fit more people than is being indicated by current operating conditions and on-the-ground reporting.
That said, not having the more accessible seat available on every train was an unforced blunder that they should have seen coming. Though I wouldn't be surprised if they just copied what they did in Shanghai, which similarly does not have the accessible seat on every train-I'm not sure I ever saw it there, even though I knew it existed. But Disney-people in America are bigger than people in Shanghai. It doesn't take a rocket scientist to know that. C'mon.