Dev Diary #221 talks about balance changes and QoL improvements being added to the Lem update:
https://forum.paradoxplaza.com/forum/developer-diary/stellaris-dev-diary-221-balance-and-quality-of-life-improvements.1488586/It's quite a list, and the devs made it clear they didn't cover everything, but to sum up:
- Void Dwellers, the Shattered Ring origin, and Ecumenopolises are all getting a bit of a revamp.
- The Industrial World designation now splits output between production of alloys and consumer goods (you're no longer forced to choose between one or the other). The new Factory World designation is being added for planets specifically focused on producing consumer goods.
- Hive Worlds, Machine Worlds, and Subversive Cults are all getting a buff/rebalance.
- A number of Civics are getting beefed up a bit, and a few are being nerfed slightly.
Looks like a decent, and well thought-out, list overall.
I'm admittedly a little bummed about the Technocracy civic getting nerfed, but I can't say I'm surprised. The rework to Ecumanpolises looks great, however (especially with Rogue Servitors *finally* being able to build them), and I'm especially (if oddly) happy about the addition of the Industrial World designation -- that had been bugging me in a low-key way for a while now.