Just to give some ACTUAL numbers on conqueror.
Playing it with sylas, and taking huge advantage of it early on in lane (admittedly Im a horrible player), my numbers were as follows for two games. one was short and i hard carried, one was medium length and I just did ok. Both games had similiar numbers.
healing 800
true damage 800
damage that would've been mitigated 200
Both games were VERY similiar in numbers and this is approx. what they BOTH were.
Bear in mind that this DOES NOT factor in the extra damage from attacks/abilities granted from the adaptive force, which is ACTUALLY where the rune TRULY shines. This stat is not labeled, so I'm not sure how ANYONE can say how OP it is or isnt.
Now you need to understand that for a character like sylas, in mid-late game fights if the enemy was fed and i wasn't, i rarely benefited from 5 stacking the conqueror and getting healing/true damage because I could not go in and sustain. I had to poke. This makes the rune sort of high risk, high reward also.
Similiar games with other runes
grasp of the undying (a good average of many games)
1100 healing
1100 damage
125 permanent bonus health
Electrocute (a solid average).
2500+ damage depending on the game.
Fleet footwork
4000+ healing
TO put this in perspective, a rune like revitalize can provide 1000+ shielding and 1000+ healing in a given game as the bottom tier rune.
Shield bash is EASILY generating 1100 damage in a game, not counting the bonus armor/mr
SO before you go calling it OP, know that the amount of true damage/healing from the bonus of stacking it, is actually a very minor part of the rune. And in truth, it feels about right in that aspect on someone like Sylas.
But again, that doesn't factor in the extra AP you're getting on a per fight basis, which is pretty hard to track and you don't know how much bonus damage you got from AA's./abilities etc.
But if we look at something like grasp, the damage and healing is a bit higher, and it gives you bonus HP.
If we look at electrocute, the damage is much higher.
If we look at Fleet footwork, the healing is much higher.
IDK where it stands, but OP disgustingly broken probably isnt it. Especially since the part people complain about, at least on someone like Sylas, definitely isn't broken.