So it's like... buying more businesses, essentially?
It is kinda against the current structure we have... say when you upgrade a property, it upgrades all of them in your inventory or only one instance of it?
Also it can heavily imbalance the current economy.
So then add MORE businesses then.. with the changes that have been made in the last few months we've been forced to camp to get income then forced to fight but still a battle after you get those prices up to a certain point to get that income up more & you get placed back to the needing to camp to get the income but you can't exactly have a group of people looking out for each other while people do that anymore.
I think you should be able too upgrade say for example :
Property A income : 100
Property A income (upgraded) 200
And so on for each property aswell :D