Yup.... I think it's better to go by albums. @Sth2112 post has two flagrant examples: while Darkthrone is well known to be a BM band Soulside Journey is unequivocally a Death Metal album (Deathcrush is more on a gray zone IMO). But once again don't feel limited! If you want to use Melodic Death* bands in this particular list and repeat them on the next just go ahead! There's absolutely zero issues with that IMO.I rather make as least separations as possible but that is just me, I like a minor number of some sub sub category albums and find it nicer to see them all together in death or black. If we make more categories, no prob, the lists could turn out smaller, but no big deal.
*will stop use other definitions for disambiguation purposes