RVR isnt low kicking standed opponents on his MMA fights,witch i consider he is preserving from catch leg takedowns.
it is a possible thing to consider when you fight against a good wrestler but you can improving it trowing a jab,hook or cross and then low kicking with the opposite leg,it is much more harder to catch than single low kicks
maybe with more MMA fight he is going to train for this specific problem and start to be more confident on low kicking guys in standup MMA,but i rather 10000000x on watching him only kickboxing