Hi,
couple thoughts... The fuse has been added so if you ever have to drive on a donut spare tire, you can switch to FWD and not worry about putting wear on your AWD system due to uneven tire diameters and grip. My guess is Subaru did not put a switch on the dash because if you drove your car for 6 months in FWD and 6 months in AWD, you wouldn't wear your tires evenly, and you risk excessive wear on the AWD system over time. Same philosophy behind always gettng a full new set of tires (not mixing and matching unevenly worn tires) on a Subaru AWD system.
Thanks.
