I think it says a lot if you compare this guy to Zubat.
and not even in a bad way necessarily, but still. Both are bats, yet Zubat is just a head with ears and a mouth, wings, and some abstract spikes for legs. and that's it. The key points of a "bat", in Gamefreak's mind, distilled down to its simplest form. and hell, they had to, graphical limitations!
whereas Noibat here, has the big ears, but they have three rings in them. He's got a defined eye, nose splotch, and this helmet-esque thing going on with the purple fur going over the black fur. midrif, actual mands and feet, he's a fully-thought-out creature. In some ways, it's a better design. I can picture it existing in a 3D space a lot better than Zubat, who always looks awkward when he isn't a flat sprite.
But at the same time, there was that simplistic charm of Zubat that Noibat doesn't really have. A child would have a hell of a time trying to get this guy just right, whereas Zubat is a piece of cake.
I'm sorry this isn't more humorous, but I'm realizing this is the 6th-to-last Pokemon, and then that's it. So excuse me for feeling a little more reflective than usual. I'm rating Noi higher than Zu, though, because when I think about it Zubat is actually just kinda booty-sweat. I guess the take-away from all this is that not all progress is bad? also dragon-bats are cool?