Honestly, after two months of being Necro as casual M+ resto shaman player, I can say that unless you constantly do high level content, one cov is just like another. I barely use Fleshcraft, a little more primordial wave but I can’t say it’s mandatory, meaning I won’t save runs because of it and I won’t fail runs because I don’t have it (or don’t use it).
Maybe for other classes or specs is different but for me as of now “the right cov” has proven to be way less mandatory than I thought two months ago.