First: is this an appropriate place for feedback on the expansion/patch?
Second: I'm quite liking this new expansion. Some notes:
1) With the changes to waste rock processing, I'd really like to see waste rock in the info bar alongside the other basic resources; it helps you plan out things like "how many waste rock processors do I need to keep up?". Also maybe give transport rovers the option to pick up waste rock... and while you're at it, black cubes from the Power of Three mystery.
2) While Japan does initially seem like it's too easy to be "hard", I'm actually finding that there's a bit of subtlety to this. While Japan is pretty amazing in the very early game, with the one annoyance of having just one rocket, a lot of its perks do a great job of getting you started. Where it really starts to drag is mid-game, especially if you're accustomed to being able to grow your population rapidly via sending more Earthborn. With Japan's very slow applicant generation, you have to put some serious thought into expanding your population locally; I only really started to break out past ~250 colonists when I built a dome with a medical center and plenty of comfort buildings. When I next play Japan, I'm going to be putting much more thought into keeping comfort levels high from the start.
3) It may be worthwhile to revisit the difficulty multipliers of 1-rocket sponsors. Between cargo pods and that one event with the mysterious rocket (thus giving you a free rocket), it's noticeably easier to cope.
4) Love the events, though the "trap" in aforementioned mysterious-rocket is hilariously irrelevant in the face of free rocket.
5) Placement of research sites can be a bit superfluous; unless I'm understanding things wrong, it's bet to separate your research domes to minimize collaboration losses, so having 4 literally on the same screen does you no good.
6) I have no idea if this is intentional or not, but after triggering some events that generated tourist applicants, I have basically a never-ending stream of tourist applicants (literally hundreds... as Japan). I know returning tourists to Earth is supposed to grow the tourist pool, so maybe this is an unintended side-effect?
7) I'm not 100% convinced the new waste rock processing plant is balanced. It's relatively slow in clearing out your giant waste rock fields (even with factory AI and overcharge, it takes about 2.5 sols to go through a single waste rock pile), and despite taking similar upkeep as a concrete extractor (1 machine parts, 5 electricity), it delivers a small fraction of the concrete. I'd consider either cutting the maintenance to 0.5 machine parts, or increasing the production and power usage to compensate.