FJR top heavy? It's all relative.
After my 35-years in the non-motorcycling wilderness, I got a new Triumph Bonneville. The Bonneville was top heavy. I dropped it about 3 times in the first few weeks, each time essentially stationary (and once by snatching the front brake at speed, not good). After about six months it wasn't so top heavy.
After a year, I changed it for a Trophy 1200. Now that WAS top heavy. I dropped it a few times in the first few months. And once after 3 years or so when the engine stalled whilst moving off and turning out of a driveway. But again, after about a year, it wasn't so top heavy.
Having changed to the FJR, although a bit heavier than the Trophy, the FJR was nothing like as top heavy.
I find the FJR is less stable than the Trophy at the back end. On more than one occasion I've wound on the Trophy and had the rear wheel spin up. The Trophy has more low down torque than the FJR (this may surprise some of you, but it is one thing I really miss from the Trophy). The first time I thought it had clutch slip until the rear end started to move sideways. It caught cleanly as soon as I reduced the throttle a bit. On a couple of other occasions it's move sideways as I've opened up, and again caught cleanly when I eased the throttle.
I've had the FJR start to slip at the back a couple of times. Both times I felt much less in control during the recovery. Maybe it's because I'm still fairly new on the FJR, maybe its suspension gives my backside less feedback. Maybe because the torque is rising more rapidly with engine speed. Maybe because the throttle on the FJR is more abrupt at low settings. Probably a combination.
In more "normal" riding, I agree with others that the FJR can lead you into areas you shouldn't go to. It is much more confidence-inspiring than my Trophy was, and I am having to consciously back off when I find myself travelling faster than I really should be. Oh, the ABS brakes really do work well. (My body may have 64 years, but my motorcycling brain is often still stupidly adolescent.)
Anyway, to sum up, top-heaviness is something you learn to deal with. I'm only 5'8 and weigh about 150 pounds; not enough of that is muscle. So I have learned to be cautious whenever below walking speed, particularly with the electric clutch that often disengages at the wrong moment. But, those linked brakes seem to work very well at low speed (until you want to put your right foot down). I'm still learning.
And, I really don't want to drop the FJR, it's SOOOO embarrassing.