Let’s evaluate every route posted.
Unova Route 18: based as fuck. Essentially the Cinnabar Island of Unova but bigger. Lot to do here including meeting Wake iirc, getting a magma stone for heatran in the sequels, getting the king’s rock, a hidden grotoe, and more.
Kalos route 1: Just no. 0/10
Unova Route 21: fucking yes. Complexity is great and mega routes always welcome. Also plenty of things to do.
Unova Route 9: Okay. It serves as a gateway to challengers cave in the originals, shopping mall nine, and is frozen over in the sequels to make for a nice ice puzzle. Also tube line bridge is pretty based.
Unova Route 5: Meh. They clearly fluffed out driftveil drawbridge by making this route an extension of it. I guess it’s better than not existing at all, even though the bridge by itself is already nice with item hunting. Triples and rotations are also showed off nicely on this route, as well as a plot point with Cheren and Alder if I’m not mistaken.