Vengeance. You seem cool and all, and I respect a fellow Sidious fan. But from what we gather, Ragnos had control of Sith Magic. Arts that were lost before Sidious was conceived. Now, granted. It wouldn't be an ownage fest as many believe it to be. But Ragnos was physically better than Sidious (even in Dark Empire), and the others faced down many Jedi in combat. Many more than Sidious faced.
However, there were more Jedi back in that day too. Sidious had no trouble in ANY of his battles (even when he was dying). So I agree that you can't necessarily say that:
"Kun would own DE Sidious. He slaughtered thousands of Jedi in battle."
Well, duh, in DE Sidious's time there were only 100 Jedi, or so. So there is no telling. As I said, it would be close between Kun and DE Sidious or DE Sidious and NJO Luke.
Ragnos is stronger. And the other Sith lived in fear of him. He even had access to arts Sidious himself did not. So I would imagine he is still stronger.
He'd beat DE Sidious. I'm sure.