Cejudo is certainly a great athlete, but let's not forget that DJ has already faced Cruz and Dodson -- 2 great athletes in their own right.
I'm definitely interested in this fight, but the general lack of interest is due to the fact that Cejudo simply isn't ready. He's only been fighting professionally since 2013, and it shows. Although he has all the tools to be a monster, he hasn't figured out how to put it all together. Hence, he's looked less than impressive against guys who aren't elite. For example, his win against Formiga is solid, but it's a split decision against a guy whom Dodson and Joe B both dusted inside of 2 rounds. To take it a step further, Cejudo doesn't have a single stoppage within the UFC -- I don't recall him ever being close to stopping someone.
Most people would probably agree that Cejudo isn't on the level of guys like Dodson and Joe B, and those guys had nothing to offer against MM. That pretty much sums up the lack of interest. Cejudo might get there eventually, but this fight is obviously premature.