Waaay too dark, you're going to need to add a lot more lights, preferably non-coloured lights, in all the playable areas to stop 99% of any feedback you get being along the lines of "too dark", "can't see enemy", "spy heaven", etc. I also can't tell what the layout of your map is from your screenshots because they're so dark.
I don't think you need the team-coloured lights in the spawn rooms, you've done a good job of using team-coloured textures in each corner, and the coloured lights, while pretty in their own right, don't necessarily help in a multiplayer scenario.
I'm ignorant of tf classic gameplay, but those look like some long sightlines. The track layout looks a bit simple, and doesn't force teams to go past all the other 3 teams. I'd suggest a spiral design that puts the green cart past the blue building, then red, then yellow, and then leads into the middle capture point. as an example, i don't know what the cart layout is below the platform.