There is talent in spining around a mop when you are drunk? There is talent in falling over when putting trousers on when drunk?
Kate had a minor talent for impersonating accents, if she was your friend you would laugh at her a bit.
Brian was consistently and deliberately/naturally funny all of the time. Dean recalled in the house waking up and laughing at the first thing Brian said when he woke up in the morning. Brian had the BB2 house in stitches most of the time. Paul said in the book: "we didn't have telly but we did have Brian".
Comparing Kate to Brian is completely over the top in my opinion.