I play the heck out of this game and even if I take a break for a while I think about it and come back. I’m playing Fallout 4 right now but I still make some time to hit my current CDDA game too.
The z-level thing isn’t a big deal to me since there’s so many structures and variety already.
I’m also not into air vehicles - would be fun - but as with MMORPGs - would be a way to shortcut and avoid danger too much. Part of the fun of the game (for me at least) is driving around to explore without destroying my vehicle.
I guess my biggest desire is more of the same. It’s nice when new buildings or variants, or items, or other content are added as it spices up the exploration when starting a new run.
When I first started playing (a couple months back, I’m relatively new to the game) I found it cool that even after playing for 40+ hours and looting obsessively that I’d still find items I’d never seen before (or find a location I’d never seen). Now playing experimental and updating it frequently I still get that once in a while as new stuff trickles in. The breadth of content in the game is one if the amazing things about it to me.