Playing A11, getting back into Rimworld for the first time in months, I found myself frustrated that colonists who were arrested for having mental breaks are so hard to re-recruit and return to productive life. After several rounds of this I finally realized I could just release them and they would go back to work.
I learned the wrong Rimworld!
Are there any other recent small improvements that make old ways of playing maladaptive?
Now that many items deteriorate when left outside, you can sell things whether they're under a roof or not; you only need a nearby trade beacon. If you're assuming trading works like it did before, and storing things you want to sell outside, you're losing silver as they lose health. Build a beacon (or beacons) inside in your indoor storage, so you can sell things that are there, and build another one outside for things that don't deteriorate (e.g. metal, silver) and as a place for items/silver you buy (and occasionally attacking pirates) to land.
Also, cremating human corpses automatically strips them now. (That was more important to know back in A10, when if you didn't know you'd still be doing a lot of unnecessary micromanaging. Now you can designate a bunch of corpses to be stripped anyway, so it's not as important. Still good to know.)
One other thing: Turret explosions are a lot bigger now. 3 blocks away instead of 2, I think. Pretty important to know if you use them.