xy are my least favorites. i don't think a bad game exists in main series pokemon so i'm not saying they're bad. for being my least favorites, i actually put a lot of time into x. i even have two copies of y. something about gen 6 overall though leaves me in a weird place. i can't describe it. but back to xy specifics, i found the games too easy, i didn't enjoy team flare or their motive and just thought they were really weak, the gym leaders are the most forgettable in the series, the rivals were really under utilized (i've stated elsewhere they could have insanely benefitted from being your respective rivals in different things like PR vids, dex completion, etc.), music was forgettable aside from a few tracks, the list kind of goes on. i think that what makes this all so noticeable to fans is that it came off the heels of gen 5 which had been highly acclaimed (especially at that time) for its story and character development. so to go from that to what xy brought us, it was a huge downgrade. and we seemed to excuse it back then bc it was the first generation on a new console since gen 4 and everyone was ready to make that jump to 3D. but i don't think xy would stick out like such a sore thumb in those ways had gen 5 not been so story and character heavy. but that can't be changed now.
it so desperately needed a z version to come in and fix these issues...and they just deadass ignored it. really the first major region to get ignored like that. every region (too early to speak for gen 8 but every one before) has gotten a deluxe version (yellow, crystal, etc) or a sequel (bw2, usum) and they didn't give xy/kalos a damn thing. they just left it hanging. like they were psyducking READY to be done with it just like we were and moved on to alola. like really thinking about it now, i wonder if that was seriously the case. like they just straight up don't like that game or aren't proud of it or something. makes me wonder.