Hey, oddly enough I just posted something that touched on blocking and refered to Zelda back in the acrobatics thread. Specifically I was discussing the lock on ability in Zelda though.
Anyway, I think just about anything other than auto-blocking would work. Auto-blocking worked nice against blaster fire, but it killed saber battles. saber battles turned into a whole lot of straffing around trying to hit the other player somewhere where he couldn't auto-block.
I don't like blocking being a force power, its used way too much, and blocking is too important for using the saber without getting mauled. I think there should be a seperate non-force induced block button (it doesn't have to be the secondary fire, and I think it'd work nice on a three buttoned mouse).
As far as people never letting their guard down in MP... here's where I've got a neat idea for you >
maybe when you press the block button, unless you get hit you can only hold up your guard for a second or so (maybe less). Of course, if you get hit, you continue to block untill the attack stops. this way you'd have to time your blocks well, and it would add a major skill factor to saber battles. It would put a k-bosh on straffing around to hit someone in the back.