I don't think tanks should have %max HP to the extent they now do
So what if tanks vs tanks become slap fests. So what if tanks auto lose to bruisers Who gives a shit. Wow, two champions that focus purely on defensive stats can't kill each other who would have thought? Wow, a durable fighter automatically shits on a purely defensive tank who doesn't have the damage to deal with him.
Injecting so much % HP into tanks have allowed them to do way too much damage on top of the insane amounts of CC they bring to the table.
It becomes so much harder to justify picking a bruiser in the highest levels of play unless the bruiser is absolutely broken (camille) or has a gimmick that can make them useful in niche scenarios (volibear new E and jax counterstrike). The vast majority of bruisers are just outclassed by tanks. Also with the way volibear builds and plays now along with having two forms of hard CC, it's very difficult to classify him as a juggernaut as opposed to just a tank anymore.
This is why the LCS is literally nothing but tanks and camille top lane, even in patch 8.4 when darius got his buffs, renekton got his small buffs, wits end got changed to favor melee and also be better at max stacks, etc.
The biggest offenders are

These tanks do way too much fucking damage. Kench you can somewhat justify that if he devours a champ he can do it with an ally and vice versa. The other three are just moronic on every level, and sion is basically permabanned.