Luke CAN'T be that strong of a jedi
Sorry Luke fans, but I just don't see how Luke can be considered a strong Jedi. Sure he has the genes and the potential, but that isn't enough. He was just too poorly trained to be strong at the time of ROTJ. Even Anakin, the chosen one needed to be trained for many years before he became powerful and even after long years of training under one of the best masters, he still lost most of his fights.
Simply because of his incredibly poor training, wouldn't he have to be one of the weakest Jedi ever?