More to do with styles.
Rory does very well in striking and every other aspect of the game really but only at a more moderate, technical pace.
When rushed and overwhelmed (A big part of Robbie Lawler's style) he tends to get all jumbled and sloppy, fighting back as best he can under the pressure but unable to relax, adjust, and set his own pace.
Daley is no joke, very fast striker, however he tends to me more technical and goes into a fight on the same playing field as his opponents.
Difference with Robbie, he says fuck the playing field and rushes in with a relentless force that forces people to change their style, getting them out of their comfort zone. This sort of style is hit and miss though, some guys know how to use this as a weakness, others are prone to it.