The situation isn't particulary hard nor controversial, only Gustaffson try to make it controversial.
Cormier is fully deserving of this title shot, not only Gustaffson already had his chance, but he is younger than Cormier and can easily wait his turn. Jones vs Cormier is now the fight that everyone want to see. Not only it's the most interesting match up, as on paper, Cormier will be the favourite even as the challenger, and taking account the bad blood between the two fighters.
Jones/Gustaffson is a nice interesting rematch, but Cormier/Jones is pure fireworks and will be hyped like never a LHW fight in the UFC.