Gen 5 didn't add anything revolutionary, but it polished everything about the series. It certainly felt different to me. quite true, the only significant change in gen V was DW abilities (and some competitive hold items) edit: and reusable TMs
X and Y are going to add something huge though. Nobody knows exactly what though. not sure where you're getting at, but the first thing on any list about what gen 6 introduced to the series will be " a new type " they can add more stuff, but nothing that will appear before it in any decent list
Don't worry about it. I laugh automatically whenever I hold sharp objects. - Machi - Nagasarete Airantou http://youtu.be/iTJtTiQYlNU
There's infinite TMs now, and most pokemon now have new abilites. The exp system has been changed, too- lower level Pokemon now get a lot more experience from fighting higher level Pokemon. Some moves and abilites have been changed e.g. Sturdy now works like a focus sash
'When thou enterest into Oblivion, Oblivion entereth into thee.' -- Nai Tyrol-Llar
The main thing I've noticed is there is a larger focus on the story now, and the competitive scene seems to be more acknowledged (in the breeding systems, join avenue, haivng the subway in the central hub town of the game, etc.) Pokemon XY seems like it might do this too. Apparently IV and EV values will be more easily visible in this game.
"Earth is a silly place. Half the world has no clean water. And the other half has so much, they poo in it."