In the wider world away from dedicated car nuts like this, It certainly is. Whether we like it or not the most popular cars in the world are always going to be performance cars of one sort of another, sports cars and supercars. That is what the majority want to see. Kei cars are just not exciting to most people. When you go on more general gaming websites/forums you always see people complaining about GT games forcing you to drive slow cars at the start of the game. I guarantee you'll see the same comments on any sites running a story about this update once it's out.
Personally I'm pretty ambivalent about it, I'll probably drive it, but not extensively. It just seems a weird car to kick things off with, not really going to make people think "Boy I should keep an eye on future updates if they're going to contain stuff like that!"