Further to my last, I've just found this on the "F-35 Cancelled, Then What?" thread. Posted by Engines on 17 Dec 11:
This is a complex one to fix and test, as the time between the main wheels hitting the wires and the hook engaging them is not fixed and the dynamic behaviour of the wire is complex, depending whether you engage in mid span or off centre.
Engines gave a very comprehensive post about the whole hook issue and the problems with repositioning it, etc.
And YES, it's so ugly. Who'd want to be seen flying that?!
Courtney