I will admit, this map is a work of art.
City 18 is without a doubt my favorite hl2rp map due to it's simplicity, however the size causes many problems as it is puny, and packs everyone in. I like that for some situations, and others it can be a problem.
As for lore, it is better to stray a little bit away from the whole City 17 thing to prevent HL2 cultists from #reking our server.
However, the map is much more light and provides larger living spaces, a larger nexus, and much nicer scenery. It all depends on what the community wants.
This is why my vote goes to:
Either/or. The community shall decide.