Jackson should be on an edge it makes complete sense, he has played most of his best football there, has a pass on him, defends well on an edge and organises players either side of him.
Statstically he has been on par offensively and defensively superior than Liam Martin this year, and that is whilst being asked to play a role he hasn't played his whole career. Your comment about not being remotely close is incorrect.
Jackson - 95% tackle efficiency, average metres 86 per game, 5 offloads
Martin - 88% tackle efficiency, 101 per game, 5 offloads.
Jackson would have done no worse than Waddell on our edge this year, if I was Jackson I would be calling out Barrett for putting him in the position he has