Fountains should be replaced with 5x5 residences because...

Fountains are pretty but useless.

This could open up new ideas for shops - can you fit a good shop in a 5x5 space? If you claim the 5x5 next to a popular residence, you could make some good money.

This could also allow for "hub" residences within the center of a 2x2 square of 60x60 residences - and with the senior staff service that allows modification of roads, you could model this any way you like. Of course, this isn't just limited to shops - you could create a (very small) parkour challenge, a challenging redstone creation, or just own it for the sheer novelty.

Should these residences take up a whole residence slot? They could - or not. It's completely up to Starlis to decide.