I quite like it. I like the large routes, which sometimes have roads, but always have another option as well.
Oh, and not visiting all the cities pre-E4? Big bonus. Opelucid City disappointed me...Sunnyshore City is better in my opinion. For me, the biggest disappointment was Dragonspiral Tower...way too small and un-maze-like for me. The graveyard tower was cool though.
I like how the map doesn't make it completely obvious how everything is connected...overall, Unova may have few routes, but many of them are simply not named "Route ??", but instead have proper names - so it's big enough. And, to be honest, I wouldn't have minded if I couldn't get Gen I-IV pokémon at all in the wild, as long as they're still around in the Dream World.