How about adding a T-shirt?

[silversun]

I think it would be nice to have a t-shirt to wear underneath the itchy wool sweater.

[Wastelander]

True, and I guess underwear-slots in general would greatly benefit in the game. 

[rla1974]

It would be nice to see a layering mechanic where one can stack several layers of sweater or long johns, but I suspect this would break the clothing game balance.

[Ape88]

On ‎11‎/‎14‎/‎2016 at 6:17 AM, rla1974 said:

It would be nice to see a layering mechanic where one can stack several layers of sweater or long johns, but I suspect this would break the clothing game balance.

Not in my opinion. You'd still be carrying that extra weight, which could make it a hindrance more than a help.