DP introduced amazing graphics and battle revolutions. Pearl is currently my favorite game because it revolutionized Pokémon. Physical/Special Split, new graphics, and different strategies brought Pokémon to the state that it has been in for 2 generations now.
XY may not revolutionize battling as much (to be determined) because we are comfortable with it now, but it is doing graphically to Gen V what DP did to Gen III.
It's obvious that they're the core games in a new generation, just like Gold/Silver, Ruby/Sapphire, Diamond/Pearl, and Black/White. --- Creator of Jay's Journey (see quote!) "It's not ten years old! Therefore, it sucks!" - Nostalgia whores everywhere
Black and White were the reboots. I think this one is going to be more about fanservice, showing off a lot of popular Pokemon in 3D. Lots of fan favorites all over the map. --- http://www.youtube.com/watch?v=iSLJJDRA-jQ Rate and subscribe. Very good best videos all the day!
So were Ruby and Sapphire. And Diamond and Pearl. And to some extent, Black and White, since Zekrom and Black Kyurem have blue tails, and Reshiram and White Kyurem have red tails. --- http://meta289.deviantart.com/#/d4j1eby The Pokemon Cycle. Don't deny its existence.