Yes Beni we all know of your semi-dictatorship over the.. what? 7 members of swtor star wars discussion? Pretty apt example of being a 'big fish in a small pond' as they like to say.
Yes breaking the Force defense of a single person with a focused attack is not the same as attacking a dozen individually, at the same time. Kun being capable of one shotting Odan-Urr, one of the strongest Jedi in the galaxy, far before his prime, comes to mind as a comparative feat. Point being the feat you used doesn't at all have similar circumstances to it.
Shaak Ti comes to mind. It isn't as if Vader's Force grip was infallible, Starkiller pretty easily overwhelmed him in return:
“You can teach me nothing,” Darth Vader’s leaden voice intoned. One black glove clenched, and for a moment the apprentice’s throat closed tight.He beat back the telekinetic attack with one of his own, shoving his Master in the chest with the force of a small explosion, throwing Darth Vader backward across the room.
-The Force Unleashed
But they aren't weak, Tionne is the weakest among them, but none of them are weaklings as you have insisted ignorantly throughout, here's a quick run down:
Jacen and Jaina, they were far from just children, they had only just fought off a pair of Sithspawn with Luke's spirit to guide them, better yet your assertion is pretty terrible. If Jacen and Jaina are nothing but children then why is it that their elder brother Anakin, as an unborn child, could aid in the severing of Reborn Palpatine's Force connection on the Eclipse, via a meld with his mother and uncle?
Palpatine weaksauce = confirmed.
Keeping in mind that they were all glowing blue with a Force meld, thus combining their strengths and dissolving their individual weaknesses as they were taught to do by Luke himself in the previous book.
Glad you brought that up actually; first of all it proves even Kyp, whom by estimation of Luke Skywalker would at least be a bonified Vader tier powerhouse by embracing the dark side, wasn't enough to aid Kun in restoring all of his powers. Something reinforced by the fact that Kyp's own senses amped by a focal point were 'feeble' in comparison to the senses of Kun's own will.
The second thing we can take from that statement is that either;
1.Kun's spirit is powerful enough to summon vortexes of intense power rivalling Gethzerion's.
OR
2.We can assume that the actual source itself is correct:
"A nightmare," Streen said, "the Dark Man talking to me. Whispering in me. He never lets go. I was fighting him in my dream." Streen looked around for sympathy or encouragement.
"I was going to kill him and save us all, but you woke me." At last Streen realised where he was. He looked around the grand audience chamber until his gaze fell upon Leia holding Luke.
"He tricked you, Streen," Kirana Ti said in a hard voice.
"You weren't fighting the Dark Man. He waa manipulating you. You were his tool. If we hadn't stopped you, you would have destroyed Master Skywalker."
I am very happy with either conclusion, especially given that Streen has used AE to defend against incoming lava and hold back a Leviathan. So again even if the feat is attributed to Kun, Streen still has very impressive AE feats.
That isn't counting Kirana Ti, one of the most powerful Dathomiri witches or Cilghal one of the strongest healers of the era. Lets not forget Brakiss, the soon-to-be master of the Shadow Academy whom only weeks after was giving Luke a hard fight due to his power, enough to manipulate the fire of a star:
He was one of the few handful of Imperials who tried to infiltrate Luke Skywalker's Jedi Academy on Yavin 4. Unlike the others, Brakiss had a true talent for The Force.- Taken from Complete Encyclopedia
Closing his eyes, the Master of the Shadow Academy began to move his hands. Zekk watched through the observation port, his green eyes widening.The ocean of rarefied incandescent gases between the dying stars started to swirl like arms of fire... writhing, changing shape, dancing in time with the hand motions Brakiss made. The dark teacher was manipulating the starfire itself!
He whispered to Zekk without opening his eyes, without observing the effect of his work. "The Force is in all things," Brakiss said, "from the smallest pebble to the largest star. This is just a glimmer of how Naga Sadow reached out to the stars and delivered a mortal wound five thousand years ago. "
- Taken from Young Jedi Knights: Lightsabers
Brakiss gave a rich chuckle. "Of course. I have no need for reinforcements-and I know you are true to your word." Luke paused to reassure himself that the Force was indeed guiding his actions. Both he and Brakiss were strong enough in the Force to sense any betrayal by the other.- Taken from Young Jedi Knights: Jedi Under Siege
With a snarl, Brakiss pulled his lightsaber from his waist. A bright red flame soared from it. Brakiss ran toward Luke and slashed as he moved.Luke's lightsaber was in his hand instantly. He parried Brakiss's thrust, smashing Brakiss's lightblade against a nearby conveyor belt. Sparks flew. Brakiss recovered, slashed again, and Luke blocked the hit.
The lightsabers hummed, and clanged as they clashed. Thrust, parry, thrust, parry. Luke matched Brakiss movement for movement. Somewhere in the last few years, Brakiss had gained strength.
Brakiss tried a series of small thrusts, little movements designed to be parried, and then he arched the lightsaber in one great circular movement. Luke didn't move quickly enough. Brakiss's light-saber seared Luke's shirt, narrowly missing his skin. Luke then matched each movement of Brakiss's.
The assembly room was hot with the sparks from the light-saber blades. The edges of the conveyor belts glowed with the heat. Luke concentrated on each of Brakiss's movements, deciding to defend, never to attack.
Brakiss swung his lightsaber from left to right, going for Luke's unprotected sides. Luke blocked each attack. The swings got fiercer, the movements sloppier. Brakiss was no match for Luke, but he was a good, strong fighter, and they would both be exhausted before this match ended.
- Taken from The New Rebellion
Or there is the famous Dorsk 81, with the other 12 students using the same meld to focus his power, he was strong enough to send a fleet of Star Destroyers end-over-end halfway across the Yavin system. He died in the effort but it is a far more impressive collective feat for the students than Marek's infamous guiding of a single Star Destroyer.
Stop calling them weaklings, you simply appear ignorant of the series, especially given that Luke chose them for their natural strength with the Force. Given that Luke says the same night that the students had all nearly mastered the Force techniques Luke could teach, then they have comparanle Force defense knowledge to Luke himself.
Exar Kun in one of his weakest incarnations is dominating all of them with Force choke, breaking through their melded Force powers and they only managed to survive because Streen manipulate air into their lungs.
Exar Kun in his prime would be quite capable of just flat-out crushing them on the spot and that is far more impressive than anything a Trayus Core amped Traya ever did. It is also much more impressive than sort of gripping Starkiller and then getting floored in return.