Frost Queen's haste bonus is what Phase Rush needs to be.

Honestly, you get a 50% haste bonus whenever you use an ability against a champion for 1 second, whereas you got Phase Rush, which is a scaling increased movement speed that starts at what? 15% whenever you use 3 consecutive abilities? Taken it goes to 40%, but that's at level 18, which games barely even last that long anymore. That's around 35 minutes into the game where you're just now getting full use of your rune, where you could've easily have picked Comet or Aery.