Honestly I agree with here -
The built in CSG editing tools are a bit sub par compared to quake but they are better in other ways.
Real time BSP/CSG Subtraction, Addition, etc. (No Geometry Baking needed)
Honestly - I think that Epic can learn from the original Quake level editors and even modern ones such as Trench Broom, Cry Designer and the like even Hammer
My personal grip about the current implementation of Geometry 1.0 is that it slows down to almost a crawl when allot of CSG is in a single Scene.
Geometry 2.0 is coming if we like it or not so it would be best to get our wants and wishes in before it does arrive.
Personally I would like to see -
Larger amounts of BSP/CSG with out slow down. I know of Hammer levels that have reached over 200k entities using default meshes and BSP.
Still no visible slow down in game.
I think that is something that Epic Games should aim for.
Just my thoughts.
Edit: Holy **** that is Source 2! - I should really check that out 