The reason why I was among the people who wanted change in the DP days is that there was just so much wrong with those old series. Bad pacing, reused plots, boring characters, half-baked concepts, and an overall lack of tension.
Despite the changes, the old habits die hard. We still have these problems. I would argue that the changes only magnified them.
BW: Even looking at it from a soft reboot perspective, it's hard to like this series because it tries so hard to emulate the OS. It tries so hard that it actually emulates the flaws of the OS. For example, Iris's dragon master is as vague and half-baked as Misty's water master plot. The pacing was awful. They didn't utilize their time wisely for Episode N and failed to develop Team Plasma outside of being a discount Team Rocket only without the interesting schism. Oh and everything about Trip. It certainly emulated the poor pacing of the OS where filler would take up so much time (Johto).
XY: This is where boring characters hit the fan as I found rivals to be half-baked. If the rival proper wasn't half-baked like Miette or Nene, then you have a highly underdeveloped rivalry like Alain. This leads to boring plots, especially Serena, and lack of tension. It certainly emulated how I found May more interesting than Ash because of a better supporting cast only without a good supporting cast for Serena.
SM: This is where bad pacing hits the fan since arcs exist, but they are way too short and choppy or are so tensionless that I don't care. Keep to the SoL stuff. That's what you're good at.