Removing from specs is what turned me off legion. They grabbed windwalkers and decided that all they could keep was punch and kick theme, removing all mystical abilities from them.Zen meditation gone, diffuse magic gutted, orbs and brews removed.
I'm playing a single class with specs giving a nudge in gameplay. I don't want specs to pretend like it's a different class, just as I detest the idea that destruction warlocks should not use curses and demonology warlocks should mostly summon demons and lost soulfire and immolation aura.
Soul shards as a resource need to be no different from fury. It's their design, not their presence that's problematic.
Warlocks have always drawn powers from drained souls, and it should stay that way.