I did find that XY's story was easy, straightforward, and perfunctory. The lowered barriers, so to speak, definitely pay dividends elsewhere, though - I've never been as invested in breeding and raising pokemon as I am now thanks to how friendly the process has become.
I do agree with BW felt like more of a progression, though you can argue that it to also tried to appeal/recreate some of the "magic" of Gen 1 itself via the concept of nothing but 150 new monsters.
One of BW's failing, however, is that the designs of the new monsters were very polarizing. And the decision to lock it down to the just 150, despite the multitude of pokemon that now exist, meant that you kept constantly running into the same monsters that a lot of people didn't care very much for. And this limit was a known problem, giving Diamond and Pearl's infamously horrible regional pokedex + distribution/availability of said pokemon - something that resulted in Platinum adding ~60 pokemon to the regional pokedex and making more of the new pokemon less rare/obtainable before beating the E4. --And this was an area where XY was much more progressive with by finally ditching the long outdated practice of a very limited pre-E4 pokedex and making a treasure trove of pokemon available as you played through the game's story.