My issue with Strenght of ages keystone.

The keystone is nice because it gives health which is fine and all.

But..

The sustain part is pretty pointless imho. Tanks/fighters/juggernauts are the ones most likely to use this keystone, Alot of them have innate sustain already like Darius or Illaoi. Fighters like Mundo or Xin also have alot of sustain. And then finally there is tanks who usually already have plenty of base health regen and tend to buy items which increase this, the same goes for jggernauts and fighters these also have decent hp regen and often buy items which boost this.

Which leads to the following point the sustain part only starts when your stacking is complete, which will take a while if you are not jungling. By the time you finally get those 300 bonus hp you often wont need the sustain anymore. It would be very usefull in lane but laningfase ends before the mastery is fully stacked.

So when would this bonus sustain actually be usefull, well in siege situations where you want to bully the opponents away from their tower or when opponents try to do this to you. But, and this is where things get painfull, you wont get the cannon minions, that APC midlaner just oneshot the entire minion wave, adn if the APC did not kill the cannon minion the ADC surely will. So the one instance where you can actually use the sustain part of the mastery in a meaningfull way, you will be denied by your own team simply because it is more effective to just clear out the minions asap.

Then there is the final part, the sustain part of the mastery becomes incredibly useless once you get a warmogs. And if you dont get warmogs on your tank/fighter you most likely have other items which boost your sustain plenty already like titanic hydra, spiritvisage or banshees. Or you already have a good deal of innate sustain.

So half of this keystone seems to be utterly useless. Which is why i see most tanks, fighters or juggernauts run either bond of stone, grasp of undyieng or thunderlords. Because 300 health just doesn't seem to hold up vs the power of the other available keystones.

My suggestion would be to do one of the following things, or a combination fo them;

1. Remove the sustain part and have Strenght of ages give more health.
2. Have Strenght of ages give half the sustain before it is fully stacked.
3. Give the sustain when a nearby cannon minion/jungle camp gets killed by an ally.