I suppose I can agree that the failure punishment is a little bit too harsh. Perhaps nerfing the damage one failed soak does by 50% (meaning you can actually heal through it) and allowing it to stack so that two failed soaks would actually kill you would be more suitable for heroic.
But the fact remains as Yggdrasil wrote above:
This issue has never been as pressing as it is right now. I've been an officer and raid leader since WotLK (currently co-lead with GM in a 2 day Mythic raiding guild) and even at our level (yes I know clearing Mythic is not an achievement or anything, but I want to give some context) we have constant issues with members prioritizing damage over mechanics unless everyone explicitly has to take part in the mechanic. Unless I continuously press the issue of mechanics over damage I feel like many slip into the damage meter minigame again and again. I don't mean to criticize every single damage dealer but I can never remember this being as much of an issue in the past as it is right now, especially as current encounter design becomes increasingly complex with each expansion.