I'm guessing if you thought the Transalp was not up to it you won't like the F800gs off road.
She is a big girl. Better than the 1150 for sure. I find mine ok off the road and great on the road and that is my compromise. You might find a KTM690 a better fit. No perfect dual sport yet! You could check some of the vids in my signature line to see where I like to go since everyone's idea of off road is different!