Personally, I don’t know exactly what the problem as such is with unavailable albums existing, apart from OCD 
I don’t care about an unavailable album existing when I don’t want to play it, and when I do want to play it then I see it as unavailable and can replace it - and if the deleting issue happens and this workaround helps, then I’d just have to do it for this one album. It’s probably more annoying for heavy playlist users, I get that.
(I’d rather that the album stays in Roon as unavailable, like it does now, because I may have made edits to it. To me, the bigger issue is the inability to copy edits from one version of the album to another)