I'm actually totally fine with that, I say, why not just go wild? Have all sorts of funky planets and themes and enemies to fight... I think they have taken PSO2 in a more fun, anything goes, direction and that allows the developers the freedom to create some pretty cool features. It's obviously working because the game is more popular now than Phantasy Star Universe ever was world wide.
PSO was starting to head that way by the end with some pretty weird missions and mini games.
I'd be okay with it if it were still in the support of a greater narrative or feeling. But these episodes are practically self contained games with little to no connection between them. It's probably good in the short term, but it yields a shallower experience in the end.
I mean, PSO2's popularity is the result of sega targeting local interests with the focus of a laser beam. AoT is popular? Hey presto, a level where you run on rooftops and bring down behemoths. Oop, that's not popular anymore? To Akiharaba we go!
For a franchise that used to go toe to toe with FF and DQ, it's kind of a miserable fate. I'm looking forward to Star Ocean and Xenoblade Chronicles much more than I am PSO2 which is sad given that I was such a huge fan of the original games and PSO1 as well.