AncientPower
The Chosen One
Except, given logic from the Jedi Vs. Sith guide, both acts took their toll on Kun's reserves:
his effort to draw the Suncrusher from Yavin and to down Luke had tired him out.
-Jedi vs Sith: The Essential Guide to the Force
Logically if he hadn't have just done that like ten minutes prior, he'd have been stronger when facing Luke. Kyp Durron literally asks for Kun's power and then thanks him when he has the Suncrusher.
No, one quote from the New Chronology states Luke couldn't defeat Kyp's 'full might' and Kun's forbidden weapons. The assertion being made is that the 'full might' of Kyp was being amped heavily by Exar Kun at the time. The indication being that Kyp's attempts without Exar Kun's 'black-ice power' 'reinforcing his abilities' are feeble by comparison.
Kyp with a focusing point is stated to be feeble compared to when he has Kun's power amplifying him. Something reinforced by the JA: Sourcebook, stating that Kun's power had allowed Kyp to defeat Luke. Something Horn and Streen echo in their own historical accounts.
He tried every defensive technique he knew but they all utterly failed, he was going all-out defensively and he still got dominated. Luke being capable of dealing with sorcery is a whole different kettle of fish though.
On two powerful Jedi, it is impressive, for a character with little in the way of TK/AE feats.
Thry were reaching limits of the techniques that Luke could teach them, obviously that isn't including Sith techniques. Luke already had learnt plenty of techniques by then and is stated to be a master of the Force in DE.
It also isn't as if these are red shirt Jedi, four of them are incredibly impressive already and have prior training, their apprenticing to Luke is to refine what they already have experience with.
We're talking about:
Kam Solusar, a Jedi Purge survivor and an ally of Luke in DE against inquisitors.
Brakiss, a top Imperial Inquisitor who infiltrated the praxeum under the guise of a Jedi prospect, the same guy who founds the Shadow Academy, causes dolar flares with his power and is capable of giving Luke ab exhausting.
Kirana Ti, a powerful Dathomiri Witch so strong she was chosen because of her potential.
Streen, who buffets Leviathans with AE and shields himself and allies from valconic projectiles.
Dorsk 81, who goes on to perform one of the greatest telekinetic feats of all time.
They are all melded together and are empowering each other as well. Not to mention three year old Jaina and Jacen, whose brother as a fetus was amping Luke via the same meld to allow him to defeat Reborn Palpatine on the Eclipse.
They aren't featless trainees who don't know anything.