Side quest are fine and dandy, so long as there are only a few of them and they are, you know, good. They have a point to them and they aren't meaningless busy work. And you know, instead of having a bunch of side quest there could be, I don't know, a longer story. I think that would be a better way to increase the amount of playing time.
Long routes are annoying and doesn't really do anything. Sure, they can make it feel more like an adventure but when you can turn back at any time then it destroys any sense of journey. All it does is make it harder to go back to get to a Pokemon center later. Sure, you can always try doing the entire route without going back but heck, you can try playing the entire game without going to a Pokemon center and get a similar challenge. I'm not saying three step routes (that would just be stupid) I'm just saying a short and sweet route. Like, remember Route 1 of the first games. Not really long right? But it was memorable because it had this sense of adventure, it felt like a real beginning of something. When I went through 119 it just felt like filler. Honestly, if it was half as long it would have been fine but this didn't feel worth it. Also, most of my problem is with the long land roads as they always have some obstacle to slow me down like tall grass that slows you down for no good reason or some sort of bike puzzle. That waters are fine since the only real obstacles are trainers and wild Pokemon.