Quicksilver

Since Quicksilver shuts down champions that rely on an ult or other high cooldown (but high impact) ability to succeed, champions like Zed have a hard time succeeding in the late game. I'd suggest an increase in cooldown to 120 seconds to allow Zed and co. to bait out the cooldown and re-engage after the ult is back off cooldown. Since this would overly buff them, keep Mercurial Scimitar's 90 second cooldown allows the same protection, but at a much later stage in the game and with a high cost component to it.