There are some good ideas that could be implemented. Things like an upgrade system would be interesting to see in a Mario Kart game, but as Ze_ro noted, that is not what most people expect from a Mario Kart game. They want a game that is simple to play. I'm sure if they wanted to though, Nintendo could come up with something that would meet the needs of the average Mario Kart player.
And, yes, the font is big. It is kind of hard to read on my tiny monitor!