>>29788392sinnoh was actually one of the best designed regions ever. it had a strong geographical layout with mt cornet being a powerful metaphor in it's own right.
decent challenge with 10+ trainers on each route and a few curveballs to throw you off. not to mention strongest rival battle in the franchise.
nice postgame with a mix of exploration, plot, and competitive battling with the sinnoh frontier. a lot of new pokemon are even locked to postgame with the trade evolution items in the wild.
a killer soundtrack with jazzy themes and some of the best legendaries out of any generation. introduction of the gts, wifi battles, underground and many more social features.
enough of a type variety with throwback evolutions to previous gens unlike gen 5/6. physical/special split, pokeradar dex chaining, the convenience of the poketch, etc.
the game had it all. no other gen introduced as much as gen 4 did, but that much weight became its downfall and it's ultimately known as "the slow generation".
with a remake on 3ds hardware, a sinnoh sequel could quite possibly be the best game of all time. there's so much to look forward to! not to mention distortion world in 3d!