Hi guys! First post. If this is a dead thread, at least some other star wars nerd will stumble upon this at some point. 🙂 The first thing that comes to mind is Durge.
Think Deadpool, twice the size, with a jet-pack and a ton of laser guns. He's probably killed more jedi than the Fetts or Grievous. Which is nothing to sneeze at in their case. The Fetts have strong wills, and sharp minds, that are likely difficult to attack with mind tricks, as they only work on the weak willed. Whereas Grievous synthesized their techniques and turned it to 11.
I think the jedi usually beat sith because their peace of mind allows for a stronger connection in the force. Maybe this is a bit out there, but when they duel it's like they wield destiny itself as a weapon. The force is sentient after all, and it tends to side with the ones who aren't about the destruction or domination of all life. IE that which creates the force.
The other side of the coin is that I think sith are much deadlier enemies to non-force users than jedi are, simply because it is their purpose to be deadly. They're not playing tug of war with the force like they are against their light side counter parts. They're using telekinesis to explode their enemies internal organs, frying them to death, or controlling their minds. Things Jedi aren't willing to do, but are prepared to deal with. Consequently, I can't think of a single non-force user who claims to have killed several sith, can you?
As to answering the actual question, while it's within possibility, flames are very difficult to control with TK. Jango used this technique on Mace Windu, and it was at least effective at letting him put some space between them for a minute.
The imperial heavy repeater rifle has three barrels in the shape of a triangle, which can fire all once. The theory being that even lined up properly, a light saber could only block two of them at a time.
Sonic weapons that emit a debilitating frequency, with protective gear for oneself of course, would throw most knights quite off balance, though a master might be able to will through it.
Cortosis armor, which may have been mentioned, causes light sabers to momentarily shut off when struck. There's also voduun-crab armor (sp?) which is a symbiotic organism which gives the wielder a protective light saber resistant shell.
An ysalamiri is a small mud-skipper looking alien that produces a small field around itself wherein the force does not exist. A natural protection from it's predators which sense their prey through the force. Grand Admiral Thrawn carried one for protection.
I also know the yuuzhan vong had a wide variety of organic weaponry custom fit to mess jedi up, and were naturally resistant to the force.