This is really looking great watabou!
I echo what others here and on Patreon have said about the numerous ways these could be useful, I'll just add one other. One could create districts for services, markets, etc. and using a VTT like Foundry and a couple mods, players could move their own tokens around the map of the district and go -for example- shop wherever they want and even make purchases without my involvement. Fighter wants the armory. Cleric wants the temple. Mage wants the potion shop. Etc. Sure, great, everyone go do their own shopping, simultaneously, while I get a little time to prepare, take notes, etc.
HOWEVER, I think something you said has merit "these neighbourhood maps are perceived as more detailed than MFCG's city maps, but in reality they are not."
OK, then could this level of detail be added to MFCG? I think, when you boil it down, people are really just looking for MFCG with this level of detail.
(Although personally I still like the idea of an "overview" level of detail, like the current MFCG, with the ability to click a district and have a neighborhood map generate from a persistent seed.)