considering GTA is basically a life simulator nowadays it wouldn't surprise me if in the next GTA you are a family guy who goes to Wal Mart to buy a TV and a new wallpaper for your house
and picking up your kids from school and all that lmao no seriously though GTA is like that
Anyway, I completely forgot that I made this thread, and found it in my history. There's some good replies here, and I mostly agree with everyone.
As for it being rewarding, of course. I mean, when I heard we would be able to customize the characters in GTA V, I thought it would be very similar to SA where you could go to the gym and gain muscle, or eat too much and get fat.
If this becomes a thing in the next GTA, then there would be a reason to customize safehouses (assuming you'd be able to buy more than one). Buying pools to go swimming and gain stamina or buying a tennis court to have an activity is a great idea. Or like I said, have certain items available to each character that fits their personalities. This is already sort of a thing in GTA V where only a certain character can buy a certain property. This would be a great way to earn money and have extra activities.
I completely agree with not wanting to ruin the feel of a default safehouse. I think those should have limited customization (or maybe none) compared to the ones you can actually buy.
And why stop at safehouses anyway? Why not customize the businesses you own?
If you buy a cab depot, then I think it'd be cool to choose what cars your cabs should be, the color scheme, and hire certain number of drivers. Customization is always a good thing. I greatly enjoyed it in SA and Saints Row. However too much customization can be a bit overwhelming to people new to the game and can be turn offs.
Also I don't really see how it would detract from the story or other gameplay elements. I feel that something like this would only add to the gameplay, not take away from it.
This is all just wishful thinking though.