The expansion seems decent, although I don't like the direction the game is going in as far as homogenization of different playstyles. I started a new game recently (before the expansion) as Void Dwellers, to find out they've reworked how habitats function significantly. Now, instead of building habitats wherever you like, there is a "main" habitat that is the actual planet equivalent, and a bunch of smaller habs that you spam around the star system. These smaller habs just buff the main hab to have more building slots and do nothing on their own. I don't like this change because it means you can't have multiple habs in a single system anymore. It also means the Void Dwellers start is much less unique than it used to be - it was the only origin where you started with multiple "planets" in a single system right from the start. Now, you just get the one, like all the other origins. Boring. AI empires also spam habitats just as much as they used to, filling every free system with them, except now the additional hab structures are also spammed, taking away all the resource deposits and applying them to the main hab for extra building slots, which is especially annoying if you don't want to use habs as your playstyle. Far from solving the habitat spam problem, it just made it significantly worse.
The new changes to machines are like this, as well. It used to be machine empires were one of two things - a hive mind or an ascended biological species. Hive mind robots you could start as, but synthetic ascension was something you had to work towards, however now can just play as synths right from the start with no need to earn it. Robots also had interesting advantages compared to biological pops, like ignoring planet habitability and immortal leaders. Now, robots have planet habitability too, albeit limited to the broader categories (dry, wet or frozen) instead of a specific one like "desert" or "alpine." Robot leaders will also die of old age unless you take the expensive "immortal" trait pick, once again taking away the uniqueness from robot empires and making them play more similarly to organics. You can also have spiritualist robots, which goes against one of the game's established limitations of spiritualists being anti-robot and especially anti-synthetics/cybernetics.
It's just a disappointing direction to see the game going in. It feels like the devs are getting bored with their own game and changing things just for the sake of it, or maybe it's new devs with different ideas throwing out the old stuff. I dunno. At least you can revert the version back to older editions, I guess.