@bbc.reporter, yeah this is a mandatory fight for Naoya Inoue as ordered by WBA if i'm not mistaken. As you can see in the picture below, the number 1 spot is vacant while Ramon Cardenas is ranked number 2. One thing i don't like with Team Inoue or maybe Top Rank is that they keep feeding Inoue guys who are not popular that could draw crowd in the stadium.
The last time I saw inoue face an evenly matched opponent was in his win over Marlon Tapales, although Tapales was loss at the time, but he was able to give inoue a very strong fight up until the 10th round, but after that it was just like you said where it seemed like inoue started playing it safe and targeting opponents that were not as good as him, so this sparked a lot of comments and criticism from boxing fans including inoue fans, who want to see their hero face a more balanced opponent, instead of fighting Cardenas, I am actually more interested in seeing inoue face Akhmadaliev in the next fight later.