As others have mentioned, I'd really like to be able to do things once you get somewhere. Also being able to set up functional outposts that allow you to do more things once you get somewhere. With all of the stuff we've seen with colonies and such I feel pretty good about this being adequately addressed. I'm also excited to see how mods will expand even more on this.
Something that I don't think anyone else has mentioned: rate based joystick control mode, as opposed to impulse based control that KSP (and orbiter back in the day) used. I'm fairly certain that this is how historical spacecraft fly-by-wire hand rotational controllers worked. I know I've seen doc's that support the use of that mode in Gemini. I don't know about Apollo and Shuttle but I'd guess they also had that mode.
For those wondering, it works like this: Joystick (Rotational Hand Controller) pitch back 50% corresponds to a pitch rate of 3 deg/sec. Those numbers are made up but you get the idea. Returning the stick to 0 would null your rotation rate. It's a little thing, but would be fun to "fly" a spacecraft using joystick in that way.
I have zero expectations that such a mode would actually be implemented.
As a side note, I'd love to see 3D mouse support carried over to KSP2. It's a real niche thing, but is kinda fun. I think it'd be extra fun to use with rate based controls; really give you that feeling of "flying" a spacecraft.