I don't (really) want to step on anyone's toes here,
but to be a true cyclist (motor or pedal) you must EMBRACE bad weather.
You must, must, MUST!
A cheap rainsuit will get you through a lot of garbage weather.
Since you do want to slow down quite a bit in bad weather, it would seem as though the slippage issue with FDs is not as serious as it might seem on the surface.
Now repeat after me:
"Bring it on, Mother Nature... You won't stop me!"