Routes are really important! They connect a town to another town! As many others said, it will not be cool see a town right after another town! Routes are cool because they are unique, there are no equal routes, it's a place where you can catch wild pokémon to join our team and it's a place to train! Yeah and I know that there are some routes which are a bit annoying because of the trainers, but hey, without them probable your Pokémon would not be so evolved!
My favourite routes, hmmm! I'm with Hikamaru, I love snowy routes especially from the Sinnoh Region!I always loved snow, and that white colour makes me feel, happy, I don't know! I really like forests too, especially Pinwheel Forest, I love going through the logs! I love underwater routes! I love the sea, and the species that live underwater are so beautiful! Although I like underwater routes, water routes can be a little bit annoying, but I still love them! Routes I hate, lets see ... Caves .... I haaaaaate caaaaves, the worst routes ever (in my opinion)! I'm not a fan of deserts, altough the Pokémon ther can be really cool! And I hate routes with those freakin' tall grass! So annoying!!!!! I just hate that route in Hoenn, the rain and that tall grass just makes me hate it so much!
A route that I would like to see .... hmmmm, I would like to see more beach routes, more tropical routes, and more forests! A new complete route would be hmm, sky routes as many others said and maybe hmm ... I don't know how to explain ... a place full of bamboos, it would be soo cool!