On one hand, Machida's game is ready made to deal with big tough guys trying to stalk him throwing looping punches.
On the other, Romero is so strong and has a clear wrestling advantage, Machida can be cornered and clinched for long enough for Romero to try that wrestling on him.
Luke Rockhard is one of the few guys who can use his reach extremely well. Machida uses his footwork to slip and dodge attacks, that failed him utterly in his last fight. Romero won't show much diversity in the striking, so Machida should be able to have the clear advantage their, but Power is always the unknown variable. i think it depends on how durable Romero's chin is and Machida's ability to scramble away from Romero's wrestling.
Romero has shown an incredible lack of fight IQ, part of that charm makes him a fun guy to watch because he'll eat whatever just to land a bomb. I don't think i would be surprised if Romero decides to stand with Machida in this one. and it could cost him. the takedowns he does throw will probably just be to supplement his one dimensional striking game as feints.
machida 57.4% vs. Romero 42.6%