Biggest letdown about X/Y?

The most disappointing part for me was how the rivals didn't really give you a challenge when you were battling or them. They weren't very good to battle and I disliked the rival characters overall with the little gimmicks.

 

The post-game that didn't exist. It was a serious let-down when you can catch one legendary bird (after tracking it for who-knows how long), Mewtwo, and Zygarde after beating the Pokémon League

 

The lack of move tutors.

That made me horribly upset, especially post-game when I began to start playing competitively.

 

Easily the lack of post-game content. The Looker quests were certainly nice, but by far not enough to satisfy me. Also, this may be because I've played too many other games like Zelda lately, but I wish there were more secrets, more hidden areas where better items are. I feel like everything in X&Y was just there in plain sight, not providing any kind of challenge at all.

 

The lack of Pokémon
The first generation to give us less than 100 Pokémon, kind of gives us that thought that Gamefreak is running out of ideas (not counting megas as "new" Pokémon)
The other letdown being the post-game, and the lack of good writing.

 

I was disappointed with the rivals a little, but I'm very disappointed that (if my sources are correct, and the JWittz usually is) they won't be updating the game to include the new megas and stuff from ORAS. This is a shame, since they added so many in ORAS.

 

Now that I actually respect the Battle Chateau and the Restaurants as at least a partial replacement for the VS Seeker/PokeGear/Match Call, I'd have to say the lack of Post Game and the lack of Move Tutors.

 

The gym leaders were boring as heck. I thought Gen. 5 did a great job with them but the new gym leaders are so forgettable.

 

The lack of move tutors (aside from a few ones like the Pledges, Elemental Beams, Draco Meteor, Relic Song and Secret Sword)

 

The amount of new Pokémon was so ridiculously low, even if you add all the mega's it's still not enough to be an entire generation of Pokémon.

And I love the Looker quests, but I gotta agree, the post game was too short.

 

The gym leaders. They were very weak and hardly memorable at all.. even now I have a hard time remembering half of their names. The E4 is a bit more memorable due to their amazingly-designed rooms but that's all. Diantha was a pretty big letdown especially, she felt like a much more underwhelming version of Cynthia. ;/

 

For me, it's a tie between the lack of Challenge Mode and the lack of post-game content. I loved Challenge Mode in BW2 and seriously don't understand why it wasn't brought back, especially when considering how easy XY were even if I didn't use the Exp. Share + Amie. The lack of post-game content speaks for itself: other than the Looker sidequests, capturing a few legendaries, and the Maison, there really wasn't much to do unless you're into breeding or catching them all.

 

I'm going to sound like a major echo and say the post-game. Nothing else was nearly as big of a letdown to me for X&Y. I didn't really know what to expect of the post-game when I played, so getting there and realizing how little there was to do was just kind of sad. :c

I really milked the Looker side quest, since it was essentially the only postgame story there was!

Another thing I must mention is the low number of new Pokémon. The amount of Mega Evolutions didn't compensate for that to me, personally. ;c

 

For me it would have to be the fact that the Gym Leaders and Elite Four weren't fleshed out at all. For having over 400 Pokémon, you'd think the four could have had more than just four Pokémon, and Gym Leaders could have been more interesting. I even try to go easy on them sometimes, and other than Clemont, Valerie, sometimes Wulfric, and Siebold, it really doesn't work. :/

 

The lack of a real Post Game and the rivals disappointed me the most, I couldn't stand the rivals gimmicks, they were just unmemorable and annoying.

 

The end game, the League felt a little short, and the small amount of new Pokémon.

 

Hey look, everyone else said it before me, but whatever. That lack of Postgame.