I have similar issues with my 1990 Legacy wagon, so I doubt it's ONLY a FBW thing. Last night was it was quite bad while cruising around town. Taking off became more of a problem with 11 people in the car (5 in the boot, 4 in the back seat and 2 up front - that's about a normal "piss cruise" - going off topic here, sorry) because of the fluctuating revs under 1.5K and the extra load. I managed to stall the car 3 times that night and got called a n00b driver in the process.
If it's a FBW problem in your case, then meh. I'll still be standing there scratching my head.