A reverse grib is ONLY "useful" if one has a shorter blade, and you are "concealing" it behind your forearm (by holding it against the back of your forearm). With this use of the grip, you can concievably attack an enemy off guard.
In all out direct combat, there is NO benefit to holding a sword in the reverse grip You have EVERY disadvantage compared to a traditionally-held blade. The only OTHER thing I can think of is that if you are stupid enough to cross your torsoe with your sword-arm, the reverse grip would give you a (very poor) chance at still defending attacks.
So yea, I just hate how "ninjas" and other "badass" characters always use reverse-grip styles when they aren't needed
I think it's the same. Don't let the opponent's blade touch you. Who cares if the blade can cut through anything, same principles.
The only arguement I can see being made is if lightsabers have weightless blades (I dunno). But even then, the reverse grip is impractical for all out combat since you'd still be at a disadvantage for blade reach, angle of attack/defense, and leverage.
Holding the weapon backhanded is a good strategy when you are using it as your secondary weapon. Starkiller/SA's primary weapon is the force. Also, by holding the weapon backhand you can make slashing movements faster much as you would a punch. And SA/Starkiller switches to normal grip for his duels against lightsaber wielding opponents.