Let's not avoid it. It's uninteresting and obvious, yes, but let's mention it, because it's a relevant association people would have with
Osmund as a first name.
Donny and
Marie, and purple socks. There, I said it. That didn't hurt you too badly, did it?
They come to mind, yeah - but if I met a person named
Osmund - who was sufficiently unlike a youthful
Donny! - they would not stay in mind. And if I were born today, a peer of your hypothetical
Osmund, it would be much less likely to come to mind in the first place. It's a good name. Besides, you can get
Ozzy from it (and the association with Mr
Osbourne is another big so-what). Eh... 6/10, not higher because I just feel like -mund names are sort of downbeat-sounding.