"A great song is a great song, whether it is composed by someone we can name or whether it was written long ago by someone we can't."

"Sadly it can also be ruined by rubbish production, an awful arrangement, a dire singing voice and so on and so forth."

A great song is never ruined in my opinion.
It is still a great song even if you hear me butchering it.
Dont blame the song for any of those other 'problems'