Surely OR/AS is more criticised? People don't generally consider both mostly disliked, after being played, because then the whole gen would have been put down. In any case, though, perhaps the adoption of friendly rivals, and many of them, and persistently, was grating, as people still associate such a role with Gary and Blue, because they do not like such friendly 'rival' types, or feel they express what people found cool about Pokemon and the games. While the story is probably a modified R/S/E spin-off, and people didn't mind the reliance on an 'evil team' for story-line in R/S/E because Team Magma and Team Aqua weren't portrayed as particularly bad compared to Team Rocket, and generally quite neutrally, since then it's been effectively admitted that story-line equals to there being an 'evil team,' which the games apparently like because they make them exciting, such that other than more arbitrary ways of making them look worse to some assumed players, they've probably begun to obscure that element of things more clearly. There hasn't been a 'story-line' as such separable from this since around G/S/C, where that was still border-line. If they include such as the source of plot and excitement, which was their aim, then they probably like it. Anyway, the Pokémon themselves (and listing elements of Pokémon games is just a technical specification) are also relatively obscure, as you might expect from people still after over a decade being unclear that there was such a thing as a Taillow which evolved into a Swellow, alongside Zigzagoon and Poochyena/Mightyena, and they have not made that many Pokemon as identified with the series as in R/B, which gave Pikachu, Mewtwo and Charizard, while more recent creations have generally not endured. Mostly, they don't actually seem that interesting in isolation, and mostly might come off as making Pokemon for their own sake, as they in fact are. They don't necessarily have the same sense of meaning as some of the earlier Pokémon, and are frequently just repetitions of Dialga and Palkia.
We could probably say that the legendary Pokémon since were mostly frozen at Diamond and Pearl, and the plot-lines since at R/S/E. Once you have such a plot-line, they can change gimmicks for things while relying on this for sustenance. However, it means they're unlikely to stand out. If people wanted 'stunning' regions, they might instead play 'Shadow of the Colossus,' while in X/Y regions are more likely to be placeholders or collections of locations expected, where people add the interesting things, than actual regions, in which sense R/S/E's placement with abandoned ships, shoal cave, and their water town near Rayquaza, is probably far better, in part because X/Y is still mostly restrained to an 'Animal Crossing' style progression due to graphics, etc. In this sense, outside of the graphics, which are only better in an abstract sense mostly, without this necessarily meaning much, the other aspects don't necessarily stand out from the crowd, which might bring some animosity.
