day night cycle was a modoption from BA and even so far back as a mod for TA .. but i believe it did survive as broken and semi functional thing for TECKA and ZK atleast at first.. i dont think it works anymore but if it did it would be described as an enviromental modification or atmospheric but not terraform as its mostly cosmetic changes.
the reduced sight ranges is already a mod i made so your welcome to try it but its not recommended.
something i do want is a chance to place terraform prefabs.. so you design on flat ground a terraform structure and can clone it.. with a small booklet of the blue-prints you made..
but my skills to program are very poor