I think the small tank is to make the car lighter to drive in line with the thinking when they designed the carI don't have any real complaints so far, but I'll agree with many of your issues.
- The fuel tank is small. Losing a bit of capacity to accommodate the AWD prop shaft is annoying, but I think the overall range is still acceptable. I knew the tank was small before I bought, but I knew this wasn't going to be a cross-country cruiser. I bet I could get 400 miles on the highway, which is about the same as my old 20-gallon Infiniti got.
- The cupholder/armrest issue. Going along with the rear legroom, I feel like this car could've really been perfect if they made it about six inches longer. I feel like I fit well into the space, though. I've been wondering how I could make some sort of add-on cupholder to fit into the armrest cell phone slot.
- I actually prefer manual seats. I'm the only one who ever drives it, so the seat is never moved. Might as well save the cost and weight. Manual adjustment is faster, too.