What do you think the next "gimmick" will be? I always felt the first surprise was Luke's ROTJ saber being green. It was just one of those cool little curve balls that caught me off guard when I saw it in the theater at 6 years old. Maul's saber was an obvious choice, and Dooku's a little less expected. What's left to do? Hopefully nothing, in terms of lightsaber design at least. It really annoyed me a few years back when you'd hear rumors of Jedi wielding things like lightsaber axes and such in Episode 2. Or the one about Dooku's blade being shaped like a schimitar. The lightsaber is a sword plain and simple, with little room for variation in my opinion (other than color, hilt design, etc.).
Personally, I'd like to see lightsabers used in different ways (like the whole using two at once thing). I think it be really cool to expand on the throwing technique Vader used in ROTJ. If we get a chance to see Anakin/Vader actually taking on many Jedi at once (which I don't think we'll get to see, but maybe), it'd be interesting to see him use his lightsaber in that way. It would be a nice visual way to show that tapping into the dark side lets someone do some pretty wild stuff. I don't mean that it should fly around like a boomerang or anything. But it'd be cool to see the look on an opponents face when he does it (Yikes! No Jedi has ever done that before!) Anyone ever play Masters of Teras Kasi for Playstation? Remember that full-metered force move Luke and Vader can use? That's what I'm talking about. Just fight normally and then out of nowhere, let it go.