I worked with a Kevin (Irish background though born in UK) and he was a good bloke. So I'm definitely not anti-Kevin.
I was trying to list all the boys from my class at school in the 90s the other day, and went 'Scott, Keith, Danny, Darryl, Barry, Jason, Kevin...' and DH stopped me and said 'You can REALLY tell you went to school in Essex from that list of names alone'....
I won't have a word against Alan, that was my lovely grandad's name. And Alan Turing.
And I'll sing the praises of Jane till the cows come home. Jane is a great name, also like Janet and Jenny too.