it is their first season so problems and lack of pace are to be expected. Corser is one of the best development riders on the circuit. Aprilia are doing better, but have years of experience with previous racing, this beemer is new and they've only participated in endurance racing in the past with the boxer twin, a different style entirely.
if i was still well enough to ride i may well have a BMW GS of some sort. i've had loads of big trail bikes including a 1989 R100GS, 10 gallon Ascerbic tank, single seat/extended rack conversion and panniers. i learnt a lesson. they are capable of doing the sahara desert, but never buy one thats done it as they fall apart
i had an Aprilia pegaso 650 single, same as the F650 in all but a few details, fun and handles well.
nearly bought an F650 Dakar, but went for a triumph tiger 900i instead. havent been able to ride since 2002 so a bit out of touch, but an 800GS sounds like a good balance. not too heavy, but with good power for off road excursions.
i'm now banned from bikes by my wife as my neck wont turn enough to see anything and my shoulder and right arm cant hold it like it would need so i follow the wsbk and motogp religiously.
best
Graham