I think his kicks are still as good as ever, he just forgets he has them for some reason. First 6 minutes or so of his fight against Vera he was throwing them hard, and he even landed one hard enough to kick Vera's legs out from right under him. And in that same fight he put his knees to good use when he had Vera on the cage, so we know he's still got knees & kicks in his attacks.
You don't forget one of your main weapons, IMO, my bet is he is not confident the knee will hold if he kicks as heavily and freequently like before, so he saves his shots. Life B EZ may be right about he also being worried about take downs, but he did not forget his kicks, no way.