CHIME NOISES INTENSIFY
I did notice this a bit while playing. I noticed the box cover, the first gym, Opelucid...
But also, what about Iris and Drayden? Isn't it ironic how the young vibrant girl is the gym leader in the old version of Opelucid, while the old stern man is the gym leader in new Opelucid?
Also, (this is something I just noticed) but Marvelous bridge and Village bridge are kind of opposites, aren't they? They mirror each other, with one being very old and historic, while the other is new and very technological.
As for ways they could have made this more apparent, it would have been interesting if one half of Unova was very, very technological, while the other was very old. (it kind of is, but not to an extremely noticeable extent)
Overall though, they did a very good job bringing out this theme. Especially with the visual differences between versions. :D