>Pros:

Music is well orchestrated
Characters more fleshed out
Contests are made better
A lot of tedious parts of the game are removed
The Pokenav is improved (Dexnav, Buzznav, Area Nav, PlayNav)
Delta Episode (Mega Fug)
New Mega Evolutions
Cosplay Pikachu
Soaring
Easier Breeding
Better Shiny Hunting
Fly is allowed in between routes
Super Secret Bases

>Cons:

Much easier
No Battle Frontier
Dungeons are cut out(includes safari zone)