I guess I should weigh in here as I've been a key (only? ) element in the drive for a map rotation within the coders Github contributors.
Multiple distinct maps do a few things from a gameplay perspective:
Alters the balance of departments slightly, and enables new strategies
Freshens rounds providing a new feeling. This novelty will wear off eventually - but it'll still go a good way to making rounds feel less samey.
Provides new opportunities for bored civilians
Reduces the ability somewhat to know if a single hair is out of place in maintenance, like people do currently.
I'm a big fan of having multiple maps to keep things feeling fresh and interesting. Its also interesting to watch different strategies get imployed by antags.
I don't think anyone thinks that way, and thats certainly not the objective. If we wanted to be like TG we'd rebase to TG. This seems more like a petty comment that a legitimate grievance so I'll gloss over it.
It does indeed add more things to maintain - but - Metastation, which is what is causing your complaints in the first place, has been in our code (just left to rot and be poorly maintained) for years. I've been taking it upon myself to update it and get it to live-quality. However its already been the case for the last year that changes had to go on both Meta and Box. Ultimately if Meta (or Delta) and subsequently a rotation results in attracting one or two additional contributors its even a net gain.
Ultimately we're a community that trends higher than average with people that do not like change - and as such people get really defensive and even often vitriolic over change... change agents need to be able to progress, and people need to be more patient and give things a chance.