The last fix Conqueror needs (not a troll post)
The fix is to cut down on the number of stacks a single, multi-hit ability can grant in short succession. Making it per-ability would work for some champions, but not all of them. Specifically, it'd work for champs like Riven and Kled, whose abilities have multiple instances of damage on one cooldown, but wouldn't work for those like Irelia and Hecarim, who simply have abilities on very short cooldowns.
So the way to implement the effect to work for both cases would be to put a built-in timer on Conq, so that it will not get stacks from the same ability within 5 seconds (like it already does for over-time effects).
Doing this would, I think, alleviate the problem enough to avoid another complete overhaul of the rune (or deletion). (and it would open up room to buff its numbers, making it more available to the champions who don't stack it by spamming one ability)