I would make one suggestion and i hope so, that the serch was right and showed me the topic does not exist.
I would suggest smaller shops in the space. You can only sell 4 products each shop, that unrealistic for me, but a shop like a supermarket needs a space of 3x3.
Thats a rather big ground for so a small shops. I miss retail shops with a space of 1x1, 1x2, 1x3 etc...
So my idea is:
1) that the shops become smaller in area
2) or you could raise them in floors and number of products, the shop can sell.
The prices of ground are also very high in comparison to Capitalism 2