It could still be baked in as a passive for the Shadow Priest themself, as a personal survivability buff it would work great, without adding to the problem of smart healing in raids.
Around 15% personal Vampiric Embrace would be an awesome replacement for Flash Heal for example. Maybe closer to around 20% if they were to also remove Prayer of Mending and Renew from Shadow. ^^
Would allow cutting down on Shadow healing shenanigans, without being too hard of a blow to personal survivability. Shadow's Flash Heal spam would then finally be a thing of the past, something I'd really welcome as standing still and spamming heals just doesn't fit into the Shadow kit at all.