Would the cap being at 60% be too much? I feel like even if you're Varus charging a full WQ on a blighted opponent, just 12% on QR (do blight procs count for QB ?) might not make up for the lost damage from IE (I mean, not that you'd ever go crit atm bc our magnificent lord and savior, AP Varus, and on-hit being just plain better than crit rn) Though I guess that's what pbe is for. Love that lost items are getting a touch-up !
The crit damage is supplementary to the increased CDR. You have haste on the item, haste refund, AND bonus damage on spells. So whatever % increase in damage you get from crit is exponentially increased because you get more casts.