I agree to an extent. The problem with balancing tanks comes down to the way resource allocation is along with prioritization in team fights.
A non support tank at the very least needs effective wave clear damage to not get pushed under turret. This isn't as simple as have items that only dmg minions or have intentionally tanks champs deal more dmg to minions. For one is the items are really effective it will probably be bought by champs that already have effective wave clear for no other purpose then to insta-wave clear for pushing or make situations for the enemy that much more unfavorable. Giving intentionally tanky champs the bonus damage does the same thing allowing them to insta clear with few dmg items that would still be handy for them in fights.
Another issue isn't the damage a tank does over time but instead the damage they do relative to the rate they are damaged. It doesn't matter if the tank does very little damage over a long period of time, if the rate of damage beats the relative percentage they take then they are still going to be too strong ad favored thusly. Making the damage rate to low only makes their lane before items that much harder being bullied way more.
What league could do to satisfy the players desire is to make a tank that does damage to minions based on items how ever all AD and AP values are converted to HP or Resistances vs champions. Longer CC isn't a good idea as the long lengths that already exist are pretty devastating as it is. However having A passive that results in and additional 5.5% of CDR as additional CDR per level going beyond cap could achieve the same end while giving enemies a window early that closes in over the games duration: level 1 with 40% CDR= 42% CDR, at level 18 and 40% CDR would equal 80% CDR. With cosmic insight this would become 90% at level 18.
The abilities, base dmg, and cc durations could be balanced to mid to late game. This would make for a champion that struggles in lane without to much to do about it. They want to pack on levels, CDR, and Tankiness as quickly as possible. When mid game hits this champion could still have an issue getting onto targets without help but when they get to enemies they would become a menace to everything they want to do. This champion could be really hard to get away from, get off someone, or kill conveniently enough under the context of a team fight.
Even when they start becoming powerful in what they provide for their team their dmg could still be extraordinarily low being beaten by supports even. Pretty much if one catches you when its alone you having nothing to worry about at all at it will probably run out of mana before it can come close to killing you, if anything you will fear he is buying his allies time to come over and kill you.
This champion could be skill oriented still so long as the cc effects depend on how you combo abilities which each individual ability providing only soft cc and various combos providing all kinds of different hard ccs.
Q-slow
W-root
E-knockdown/disarm.
Q-W=stun
Q-E=Knock up
W-Q=displacement away
W-E=displacement towards
E-Q=Sleep
E-W=Entangle
Q-W-E=longer stun duration
Q-E-W= Knock up multiple targets
W-Q-E=Displace way further
W-E-Q= Pull in multiple targets
E-Q-W= AOE sleep
E-W-Q= Entangle for a longer duration
R could be and AOE from the champion that cements it as the ultimate undisputed cc specialist by interrupting all targetable enemies abilities and attacks instantly within an AOE range around this champion including Malphite R. This ability could be on a significantly long CD at the start but after some points and 90% cdr at level 18 and 45% cdr be up with considerable frequency enough to become one of the best late game abilities there is.
Well any way I trailed off the point. League has done a good job at inventive ways to deal dmg but has fallen short of ways to makes playing tanks feel good and rewarding without making their dmg excessive on top of everything else they have going for them.