This only works for gunslingers and dps jedi knights.
Why wouldn't it work for single-saber Jedi wielders or anyone who uses a pistol?
I guess a consular could do this, but I don't think the stats on the hilt would be very useful (since the only offhand lightsaber available should be for Jedi Knights). Also, they would have to take the Jedi Knight offhand token, which would mean you would have to have a Jedi Knight in your group that doesn't need it. As far as other classes that use blaster pistols, I think Bounty Hunters are the only ones, and yes this would also work for them, as well as dps Sith Warriors.