I know there are lots of threads on this, and that there are also different ways to approach the problem. My solution isn't meant to minimize the value of all the other solutions out there.
The 06 AE that I own has larger diameter grips than what I am used to, and as others have noted, the throttle is stiffer than that on most bikes.
I was a bit put off by this when I got the bike.... I went to a local dealership and bought a cramp buster to see if I would like it as a solution.
I did not get along with the cramp buster at all. It got in the way too often... I agree with the folks who point out that it can be moved around without too much trouble. But my feeling about it was that it was something that could get me into trouble. The FJR has a pretty powerful motor, and I was not comfortable with the control I had in maneuvering at low and intermediate speeds. I took it back to the dealer and traded it for a 3/8" drive T-handle.
My solution has been to pay careful attention to the gloves I wear when I ride the FJR, and to build up my wrist and forearm muscles. The exercise improvements took about a month, but it had benefits beyond the improved comfort for the right hand. The primary ancilliary benefit is that I have much better general throttle control... and this allows me to avoid the TPS problems, which I think others tend to describe as the herky jerky throttle. I tend to keep the throttle above the TPS zero, and I find when I do this that general throttle control is smooth and the bike behaves in a very predictable way pretty much all of the time. I realize that this solution may not be for everyone, but I am happy with it for my own case.
If I were going to make any changes to the throttle at this point, it would be to add a real cruise control (as someone else mentioned above), but I don't even want to do this. The more "comfort" oriented stuff I do to my bikes, the more quickly I become bored with the ride, and the more likely I am then to stop paying close attention. If I push my Sport Touring type bikes toward arm-chair mode, I end up with something closer to a sleeper sofa.... I hate when that happens....