I have missed most of the DP episodes because honestly i lost interest in the anime, i wanted to check out the 1 hour special just for, you guess, Kotone and the nostalgia of Johto.
So, overall, i think this was a very entertaining episode. Kotone turned out to be a good and charming character which i would like to stick around for a lot more, a filler season if possible, she has an interesting party (mostly because of Girafarig),she is a trainer which is nice because there are many female coordinators, even Ash is into that too. Her voice is not annoying.
Team Rocket mecha was insanity, i agree with it being the best mecha ever, not the classic filler episode three-boxes-sticked-together mecha they use all the time. Wobbuffet using mirror coat, it's good seeing that thing into action.