I believe that nintendo has been dropping hints for the graphics in later pokemon games lately
examples:
look closely at the poke center/mart in r/s/e,
it looks like a non 3d version of the same building in d/p
look at the trees you can cut in r/s/e,
they look similar to the viridain forest trees infr/lg
in fr/lg if you look at the summary for a pokemon it jumps,
in emerald (and later games) the pokemon move when you look at their summary/ send them out
It could also mean that they got lazy and just updated older graphics though...
examples:
look closely at the poke center/mart in r/s/e,
it looks like a non 3d version of the same building in d/p
look at the trees you can cut in r/s/e,
they look similar to the viridain forest trees infr/lg
in fr/lg if you look at the summary for a pokemon it jumps,
in emerald (and later games) the pokemon move when you look at their summary/ send them out
It could also mean that they got lazy and just updated older graphics though...