2007 hex head R1200GS, I have a pyramid mudguard extender.... never seemed to help.
I wonder if tyres are part of it - I run road stuff, and been a long time since I had a tourance on there. But fairly sure the first ever foot soaking episode was in one 10 min downpour on that tyre. But the road tyre does get a lot more clearance to the front mudguard and you do see lots of water at the fork leg / mudguard area (which is the part I hoped to cure with my last mudguard extension)
re. the back of one's boots getting wet/dirty mentioned by someone earlier... never noticed this ever. I have a carbon hugger on the back, to which I added a 3" extension at the swinging arm pivot end, to stop the shock getting covered in detritus (goodness know what those idiots were thinking when they made it...)
On my KTM 1290 SAT I have a big issue with something on the front end... used to be normal and now a mega front end vibration at 110mph its like the worlds worst ever wheel imbalance. Dealer suggested taking off the top box (small touratec one) as they had issue with another customer "and that fixed it" …. but that's always been there and I can't belive that could make it do what my bike does.
all I can think is either some odd aerodynamics issue with the fender extender I added on the KTM.... or the last software update that broke the suspension both ends!!! has created something odd inside the forks !