Carmack might think that there are certain areas he will be better due to decades of experience. Overall programmer isn’t a bad qualifier at all, it’s actually making it sound less offhand and more honest.
You can find a formulation that doesn't sound sycophantic without including a qualifier that could be misinterpreted as backhanded, because on a bad day it will be.
(Especially if you are complimenting a person with ADHD.)
2) avoid qualifiers in personal compliments (unless ironic)