After years of Team Rocket having funny irrelevant scenes during Ash's big moments, it sure is strange for Ash to be the one intruding on Team Rocket's moment. In fact I find Ash more annoying here than Team Rocket ever were in that regard!
Anyway, this was a good episode. What I like is that it's technically a Team Rocket filler. Unless you want to count the Genesect scene and the small set up with Team Rocket's tracking device, it was all filler really and it's the single most unique Team Rocket filler out there. Not even the TR fillers from BWS1 broke out of the usual formula.
I really don't like serious Team Rocket but they actually seemed very likeable here. It might be because they have a bit more personality than they did pre-League and because the super seriousness seems fitting for this situation. It also helps that their serious plot was actually a good one, something I can't say for their stories pre-League. It was great seeing Meowth fight like that, and I loved how Team Rocket managed to pull off a countermeasure in the event Colress had taken Meowth away from them.