I don't have any particular issue so much as I am trying to poke at a specific issue that people have been having with OC since the release, in that Tanks are just incredibly durable and can survive with 10, 11, maybe even up to 16 vul stacks if they are good at managing their mitigations, it's something I personally don't think it's as much of an issue as people make it out to be, Tanks need to be durable and a huge part of their perceived immortality in OC is the fact that only one Tank per CE needs to be an actual Tank and all others are glorified (bad) DPS, and admittedly that added safety of Tanks is something a lot of players are leaning into in OC even as we speak, and even if I disagree with the point, I understand where the feeling of anxiety, of feeling like Tanks are god's favored child and have every privilege under the sun, around the issue comes from, so I'd enjoy to address them even if I find the concerns around the issue overblown.
So a feature that discouraged players from leaning on that safety could be really beneficial to discourage that behavior, it would have little impact in gameplay, the Tank would still a Tank and players who want that safety would still have it, but there would be something of a penalty, or more accurately the absence of a bonus which I find extremely important as a distinction, you wouldn't be penalizing someone for playing that way, you just wouldn't be giving them that extra pat on the back for it, and even if someone did feel penalized... well, they visibly played like shit, so if they want to no longer be, they are going to be pushed to at least try to improve, and by creating a bonus that Tanks can't achieve by simply being Tanks, it also attempts to alleviate people's anxiety around the point.