I would make it so FScy makes your next Frost Strike Hit 5 targets.
“A sweeping attack that strikes all enemies in front of you for (23.2564% of Attack power) Frost damage. This attack benefits from Killing Machine. Critical strikes with Frostscythe deal 4 times normal damage and make your next Frost Strike hit 5 targets. Deals reduced damage beyond 5 targets.”
This way we could take Razor Ice + Shattering Blade.