I've been riding touring bikes for 20+ years (mostly Wings), and sport-tourers (the FJR) for two months. I would love to keep both, but it isn't practical - I can only ride one at a time. One of the biggest factors in the decision will be ... how is the FJR on long trips? The Wing is pretty much ready for long rides right out of the box. Not so for the FJR, but with the difference in price, one could add a lot of farkles to an FJR and still not be close to the price of a Wing.
While my experience on the FJR is limited, one thing I have noticed is that it adds to the fun of a twisty road, but does take away some of the feeling of accomplishment. The FJR handles so well, it makes riding through twisty roads very easy, and very fun! The Wing handles very well for a bike bike, and riding through twisty roads is always fun. The difference, for me at least, is on the Wing, when I've ridden a twisty road well, I feel like I've really accomplished something!
It's a big decision - but it doesn't have to be a permanent decision - whatever you decide, if you aren't happy at some point, you can always go with the other choice!
Suar