Mr. A has two qualities.He is kind. He is aggressive. He is more kind than being aggressive. If we say: 'His kindness dominates his aggressiveness.' 'His kindness overshadows his aggressiveness.' 'His kindness surpasses his aggressiveness.' Which one is better?
If you want to say that he is more frequently kind than he is aggressive, but that he nevertheless can be aggressive sometimes, then "dominate" is probably too strong a word, implying that kindness is always the dominant feature.
I suggest "moderates".
Moderate, verb: To cause to be less extreme, intense, or violent. Source: thefreedictionary