Galactic was great for how they appeared throughout Sinnoh and interacted more often with the protagonists, but these last two episodes by themselves have been some of the best in the series.
There's a greater sense of dread to me with Team Flare. Spear Pillar was literally a black void of nothingness (and a serious disservice to the source material...), where you couldn't really tell what sort of impact the manipulation of Dialga/Palkia was having on the real world beyond spooky black clouds. Here, you've got Lysandre appearing on TV screens and mobile devices around the Region to announce doomsday, all after leaving the heart of Kalos in complete ruin, and having his flunkies terrorize people on the ground further. It's ironic to me that while controlling Zygarde isn't on the same scale as the Space/Time Pokemon, he still feels more like a man in total control because of how much we actually see going down. And literally every major character in XY is pitching in to stop him.
The pacing wasn't as good, but I do still like what we were given over time. It's done a better job at getting me to care about the characters. We had Alain as a secondary protagonist [unwittingly] working for them to protect others, and through him Lysandre has a more important role than merely being the big bad. He was Alain's boss, he has Chespin in the hospital, and he was seemingly a good man working for better causes. All of which helps to make today's episode more impactful. Alain breaks down, Chespin needs to be retrieved, we get Team Flare's history of helping the needy, etc. We also had the Zygarde with thoughts and feelings during Z, so its more than just a powerful being tied to a leash now. It's "Puni-Chan!!", which grants Bonnie further relevance, and Z2's hatred of humans lines right up with Lysandre's motivations.
So basically. The low key buildup took a damn long time, but ¯\_(ツ)_/¯ the payoff is totally worth it.