This post is kind of a reductive assertion of my goals.
While I can see the paranoia, with how tanks can already take a while to die with their 30% DR, self-sustain on AOE, and defensive CDs, keep in mind, my suggestion isn't saying to make all tanks sturdier. It is examining the capacity for your progression of skill as a tank to reward you with outcomes more conducive to victory and carrying versus that of other roles. Of course, my post happened to have a suggestion, though the point of the thread is more an examination of the game's overall design, and how improvements of your skill as a tank player scale with increased success.
As for the suggestion at the end of my post with regards to tank HP scaling with Battle High: The impact is good tanks will become sturdier more often. The average tank might get like BH1 or something, thus the capacity to kill them would be roughly the same. Keep in mind, while tank longevity has the capacity to drag out a skirmish, one of the tank's primary functions (aside from using CC to set up picks) is to disrupt standoffs and initiate fights to begin with. Things conducive to breaking formations and resolving a battle. Thus, it would better facilitate good tank players advancing to pressure an enemy alliance if they could play more aggressively. In addition, it makes sense for a role defined in part by its defensive attributes to survive longer with Battle High if DPS with BH are killing them faster or healers are healing them for more. Especially because, in this case, this is raw HP as opposed to mitigation. So if you are taking more damage than you are being healed for, you are still going to die.
As a side note, yes, I do think the game needs to do a better job at providing its players with information, covering some universal fundamentals, etc. I think facilitating player learning is good, though this thread is not talking about an absence of skill. It's obvious someone who is new to the game or not using their buttons is not going to contribute well. It's talking about how much skill scales with positive outcomes for a role relative to the same improvement on a different role.