A Few Suggestions

I think the chat window would be better if you could have a window for ooc speak and system stuff, and another window for in-game speak and emotes.

It would be neat if the customers made comments as they walked around the mall. "What a great store." etc Kind of like the stuff from Roller Coaster Tycoon.

When someone opens a mall, allow them to choose what they want to sell initially, or make some change like that to the starting store options. After all, not everyone wants to sell shoes

The game needs a help file of some kind.

I would be great if you could name your store in a way that it showed it to people somewhere - maybe a special label field that shows the store name you're next to or inside of.