To tackle the problem, one must first correctly define it. It does not seem to me that the problem is tank self-sustain. Considering that the game is balanced for Savage, and that these abilities are mostly fine in Savage, I don't think the issue can solely be attributed to tank design. Rather I think this a compound issue of tank design, healer design, and fight design. So basically everything except DPS design.
Healers need a total redesign. Their design is completely backwards of what a new player would expect. Healing has other major issues, such as not having any healthy options for future ability additions. However the fact that it is so completely backwards of what you would expect is honestly enough to rework the entire role.
Fight design's problems stem from being too focused on large hits every minute or so, auto-centering, not enough damage to warrant healing outside of savage, etc. I think the biggest issue here actually is the gap between an expert dungeon and Savage in terms of difficulty. Obviously an expert shouldn't be as hard as Savage, but the gap shouldn't be so vast that abilities are massively over tuned for normal content either.
Tank design... Look, tank self-sustain is the least of the issues with tanks in my opinion. Ever since the removal of TP and Enmity, tanks have just been boring. Mitigation isn't fun, and rotations aren't fun. That didn't used to be an issue because you also had to watch enmity and TP, which was just enough to make it fun(especially in casual content where DPS never used enmity dumps). If your goal is to actually fix tank design, then you have to address the whole issue. Which probably means redesigning tanks so that their mitigation and rotation interact with each other.
If your whole goal is just to stop one or no healer runs in trials and raids, then the quick solution is to either increase the MP cost of Paladin's magic burst or put clemency on a CD. If you want to make WARs mortal in dungeons, then put a 5 target cap on BW/NF. Though those would just be band-aids on top of a stack of band-aids on top of an amputation at this point.
Looking at all of this, I can't honestly tell you what the heck SE is trying to do with this game. It looks to me that they have no idea what they are doing.