Varus passive rework idea (Based off Ashe's new passive mechanic)

So, I like the idea of her new passive. The lack of the RNG Crit is very nice and feels like it could go a long way with adcs. So I did some thinking of how I could incorporate it into Varus's passive.

NEW Living Vengance: When Varus kills an minion or creature he gains 20% AS for 3 seconds. On a Champion kill or assist he gains 40% AS for 6 seconds. While these bonus's are active he deals a bonus 150 damage + ( [Crit Chance] x [Crit Damage] )%.

Like Ashe, Varus will no longer Crit, but his Crit Animation will replace his normal AA while his passive is up. Unlike Ashe he does a tad bit more bonus damage, mainly because he will become somewhat situational on his positioning. If he is caught outside a lane/near creeps to proc his passive (Untill he gets a kill) he will be doing substantially less damage.

This could allow his W's passive Magic Bonus damage to possibly be buffed a tad, to keep it within a realm of other adcs.

Thoughts? Ideas?