Would a new Necromancer class satisfy people either though? I mean honestly speaking, we're at a point in the game's life cycle where Blizzard can't really add more classes and specs without a lot of consideration. They sorta designed themselves into a hole by centering classes on Specs and balancing 'Bring the Player' rather than a Vanilla style of having each class be unique and the Talent system simply supported how you chose to play that class. If you did dungeons, you play X spec, if you raided you play Y spec, if you did PVP then you choose hybrid X spec with a bit of Z. We didn't have this spec homogenization issue where every raider has to feel like their class/spec is balanced equally to every other class/spec. But since we're already in that mess, Class Skins would be the best way to keep supporting it IMO.
By all means, as someone who's only been interested in new expansions for the classes, we should have had a new class for Shadowlands no matter what it is.