After watching that video of Ryze abusing conquer,
This keystone can go that of two ways I think:
If mages abuse it toplane: Well then toplaners, tanks, bruisers, juggernauts, are dead I think. And it's time to quit toplane/quit the game lmao
If mages don't abuse it toplane: Then I think it's an ok alternative that i'd say is a lot more welcoming
(For example Darius needs 5 stacks of his bleed to even proc the new conquer)
this new version of conqueror is harder to proc on everyone, while it will be equally available to all champion types.
that 3 second restriction does very little to even the rune out between melee and ranged champions.
one way or the other, it will be a nerf for every bruiser whos using it now, i believe. there might be some exceptions like renekton who might get multiple stacks off his w dependent how the mechanic works.
in its current iteration it looks like it will be stronger on ranged champions. mages with extremely short cooldowns like
marksmen, and possibly even tanks. because there is nothing preventing tanks like, lets say 
from taking it into top lane and take extrended fights with you, while stacking up ap.
