The films amply demonstrate how easy it is to take your opponents hand off (and frankly I don't understand why such moves aren't attempted earlier in the fights - it seems like an automatic win condition)
It seems like about 90% of the Jedi order ought to be using synthetic hands, but that isn't the impression I get?
EDIT: To clarify: I mean specifically, why they don't attempt to slide their blade down their opponents saber more often, so as to destroy the saber and take off the opponents hand.
To be sure it wouldn't always work: either your opponent might react to disengage, or to change the angle of their hold so that you weren't sliding down their blade, or to perform the same manoeuvre on YOUR hand, or indeed to attack whilst your blade is lower than it might normally be. But if you attempted it, whilst keeping your balance and able to stop/otherwise react, then it seems reasonably safe. And as I said, if it DOES succeed, then you've pretty much won.
Seems like a pretty safe gamble with a massive pay-off if it works.