Night maps are awesome, but they require a little more care in the lighting department than daytime maps do. Usually your light_environment isn't enough to light the map sufficiently on its own (I'm talking bright enough to recognize player team colors), so you have to make up for it with plenty of lights and light_spots. Even if you have dark areas out in the open with no nearby places to put light fixtures, don't fret! You can just place disembodied light_spots above these areas, much like plr_pipeline does in this image:
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Full article I stole this from]
I also noticed that, in the corner of one of your screenshots, (at least) two of the control points are close enough to be seen at the same time. In 5CP, you want each point to be separated into its own distinct area of the map, or else a team that wins the fight for mid pretty much gets the next point as a freebie. Make the attacking team do some running so that the defenders have time to regroup!
Lastly: while you do have some displacement sculpting going on, your ground is still very flat. My best advice for making interesting ground is to build it out of smaller brushes and put them together like pieces of a puzzle. If you do that, it's much easier to turn some brushes into raised platforms and ramps, or create an area with a non-boxy shape. Plenty of height variation and cover is the key to making combat areas that are fun to fight in.