While there were plenty aspects of the games that disappointed me (no Challenge Mode, hardly any post-game content, the return of Gym Leaders & Champion who didn't really do much story-wise, barely any new Pokemon compared to previous games (unless you want to count Mega Evos.)), I found more positive things about the games and thus enjoyed them despite what I felt were flaws. I really enjoyed exploring Kalos and loved most of the cities and towns, as well as the music that played in each of them. And despite the lack of new Pokemon, I like most of the new ones and have decided to try using a majority of them at least once. Same deal with the Mega Evos.--I really like how they turned out, despite my skepticism towards them when they were first revealed.
As for the lack of post-game content, I felt the Friend Safari + easier way of IV breeding (and breeding in general) made up for it. Before XY I wasn't really much of a breeder (other than trying to Masuda Method shinies; I failed miserably, though ;;). The level 3 Hatching O-Power + Flame Body/Magma Armor does wonders in hatching Pokemon quickly, and the fact that the Friend Safari Pokemon are guaranteed at least two flawless IVs and have a chance of having their Hidden Ability makes it easier for me to get Pokemon with the exact nature/Ability/IV spread. I also really like how Hordes make it easier for you to EV train Pokemon so you don't have to spend hours maxing out a certain EV. Super Training helped with that as well, especially early game. (And it's good if you don't want a 252/252/4 EV spread.)
A few other things I really enjoyed include Amie, Trainer customization, and the Battle Chateau. Amie was an absolutely adorable feature and, in my opinion, makes up for no more Pokemon following you around (which I can't see happening anymore). Trainer customization was something I think most people have been wanting the main games to feature for a long time, and while there are some things it could've done better (such as allow for more unnatural hair colors; given the number of NPCs who have blue or green hair it'd be nice ;o;), the fact that it became reality and provided plenty of clothing options made me really look forward to getting XY. As for the Battle Chateau, it's the best place to earn a lot of cash, and is also somewhat good for training, particularly if you battle the Furisode Girls with Exp. Points (a.k.a. Audino).
tl;dr XY had its drawbacks, but I enjoyed playing them overall.