Quicksilver Sash + Mercurial Scimitar: Some thoughts

This item, in theory should be very good. It removes: Fizz Ult, Malz Ult, Zed mark, Morde Ult, Poppy's Ult, Morg's Ult, Skarner's Ult, Urgot's Ult, Vlad's Ult, Warwick's Ult, TF reveal, Leblanc Chains, Zilean Bomb, Nocturne Fear + blindness, Diana Moonlight, Darius bleed, and ALL OTHER FORMS OF CC. Why wouldnt this be a consistent buy on all ADC's?

Here's why, the active is valued at 650 gold (650 on QSS, 150 on MS, obviously there's a benefit to finishing the build). Its on a 90 second cooldown. Why would you get a debuff remover on a 90 second cooldown when you can just come back to life on a 5 minute cooldown, or an item that gives more MR and Health plus a spell shield every 40 seconds. Given that Mercurial Scimitar only removes the debuffs upon activation, Banshee's is much better. You dont even have to press a button, and if you get caught out by a WW, Zed, Malz, Diana, LB, TF, Nocturne, or Fizz you wont even take one of their abilities. How can it be better? Here are some of my thoughts. I know it will probs never happen and it will continue to be a bad choice of defensive items, but just some speculation.

Well one, reduce the cost of QSS to 1000 gold, change the build path of MS to be QSS + Null Magic Mantle + BF sword +700 gold. Reduce the Attack Damage to 65 damage, and up the MR to 45. Heres another option. Instead of a Null Magic Mantle, make it a Dagger and add 20% attack speed to the item. Or when the active is activated, give also an additional 15% attack speed per debuf removed. Or lower the Cooldown of the active to 70 seconds.

Just some thoughts.