At CT spawn you can crouch under the helicopter platform and fall underneath. If you're skilled enough you can fall to the 2nd lower platform from there too. Fairly certain you'd want this fixed just to avoid people delaying rounds, getting stuck etc.
I also feel like the water underneath should be water. Putting in a kill trigger and then having your body float on what could be an invisible water texture (just so that the splashes and physics occur) would be much nicer than collapsing against what appears to be a very hard surface.
There's a lot of ladders around the place that aren't climbable. It seems a little odd. Perhaps cover them with a metal plate so it looks like they're obviously just locked off.
As a T, travelling to A bombsite there is an area that is clipped and though you should be able to walk through it.
How is griefing by throwing the bomb off the edges covered? Or just even dying near the edge and the bomb rolling off? I don't know if there is a way to block only the bomb, but I'm fairly certain a clip_vphysics scenario can filter particular objects (so as to only block the bomb).