To be fair x2, Lumiya has defeated ROTJ-Luke before, could create Force Phantoms in the first place, and Zekk and Jaina were positive that they were no match for her. Not to mention she has held her own against Luke more than once during NJO. She's good.
I think NJO authors have distorted the combat prowess of a Jedi for people to think Luke or most Jedi/Sith for that matter can hope to defeat 3 powerhouse Sith at the same time. Even proponents of destruction like Nihilus and Palpatine would be taken down by such a trio.
"...it would be better to retreat..." - Dooku to Grievous comes to mind here. NJO authors need a refresher on the force, anyone can beat anyone, sure, but the Force is universal.
Even a weak knee Jedi with enough skill and knowledge of the force can be a threat to a powerhouse. Vader learnt that the hard way many times.
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Iboga chose not to fight, to allow himself to evolve. He had the wisdom to abandon the actions of war when he knew they would no longer serve him.
I did not see this thread. This is ridiculous. You've got Marka "I'm unchallenged for a century, surrounded by a planet full of Sith and I'm a badass" Ragnos, Naga "I make Force toys that make neophytes like Kun into Force Gods; oh and I'm wearing one" Sadow, and Exar "I take Sadow's amulet and became exponentially more powerful than any Force user in my entire era" Kun against Luke Skywalker. This is not a linear battle here, but the amount of Force power brought to bear on Luke Skywalker would be immense. Keep in mind Marka Ragnos made JA Luke crap his pants in spirit form; in the flesh, combined with Exar Kun who was likewise a threat to Luke and Sadow sporting the same amulets is overkill.