Totally agree but that won't be something I'll fix soon, if ever. First of all, adding proximity checks for the number of nearby enemies is a lot of work and might degrade performance. Second, having balanced diffculty is not one of my primary goals, I think it's fine for the difficulty to be too much with a mod especially for a H-on-lose game (that does not mean I'll purposefully make it too hard - but I think for now it's acceptable and I'd prefer to focus on other things, ie. bugs or adding new content).
In the immediate time you can play with the config file, try increasing "spawn_enemies_over_time_interval_seconds" from 8 to something like 12 (seconds) this should make the difficulty more bearable.
You can also disable Head Hunters spawn by setting ; "spawn_enemies_ignorelist":["head"],
I'd like to tweak some specific spawns to be less frustrating, in particular vines (which sometimes spawn in unavoidable places) and carnivorous plants (which are very bugged but LAGS placed them in ways that reduce bugs chance in the OG)