Throwing my hat into the ring for this. Good excuse to learn Source 2. Been a long time level creator for Unreal and always wanted to apply it to something more practical. It's been over 10 years since I touched Source, and Source 2 already seems quite fun to use.
I figured I'd go for a hydro dam level, players would ideally play on the top section, with an interior wrapping around the dam as well. Going to be taking a few liberties with dam engineering, but that's where the fun comes from 
I have a rough layout in mind - I think the curved structure would add some fun lanes to play with, though am I looking forward to modelling everything on a curve? Probably not.
I'm currently just getting to grips with Source 2, so should have some blockouts further on down the line to show. Level design is something I'm not amazing at, but I do have some lingering knowledge from Source 1 and proprotional awareness from then that should come in handy
There was also cs_thunder, another hydro dam map from cs1.1 that was featured in an operation in csgo. It's a cool theme for sure and it seems like the definitive dam map has yet to be released. But you'll probably hear about not being the first a few more times.