It's still early on in Generation 6, but XY felt like 2 steps forward, 5 steps backward.
+3D graphics
+Huge variety of pokemon to use
+A few
very standout music tracks
+
Sidequest
+Trainer customization
-Disappointingly easy, even with the exp share off
-Lack of postgame content
-Fairy type seems to hurt dark, bug and fighting types more than dragon types
-Sky Battles
-Inverse Battles shafted in favor of Sky Battles
-Story was pretty bad. Story was never Pokemon's strongsuit, but coming off of BW, I expected something of a similar magnitude.
-Soundtrack felt kind of mediocre overall
-Everything about Lumiose City
-Useless friends/Rivals
-Only 69 new pokemon
-Megas were more of a popularity contest than pokemon that actually needed them
-Shallow customization for males
-Technical issues/Framerate problems. (Horde battles are especially bad)
Honestly, the games felt really rushed. It felt like they could have been much more. Hopefully XY get the Platinum treatment.