Oh...ya that series has some way OP characters when they really shouldn't be that OP. In fact I don't think its canon anymore due to TCW.
Incorrect. Its still very canon.
Luke has done feats that no other has done. Walking on lava, becoming immovable by the gravity of the center of galaxy, creating a blackhole, teleporting objects, having the strongest force push, being the most skilled lightsaber duelist ever.
Thats why he is the most powerful there is. He has done so much more than what I just listed.