MF has been my most since Season 2.
I believed Riot would make a great rework on MF but it's not yet satisfying me.
(The new skin is pretty amazing. luv it)
If any of my suggestion is taken, I believe I can see MF in pro-games.
A. Unbreakable passive DURING W activation.
We already have a champ w/ similar power-level kiting skill, Kalistar.
So I believe it wouldn't make MF too much OP but MF could get her own concept. (Kiting w/ mobility)
B. add AS scaling to R
Remaining total DMG of R, make channeling time shorter according to MF's AS. (max reduction 1 sec)
Currently, it needs 2 seconds for 8 bullets. (0.25 sec/bullet)
If MF can burst her bullets in 1 second w/ 200% AS, she would take less risk in team fights in a late game.
C. simply buff W (20% AS) => W AS 40/50/60/70/80%
Currently, it's 20/30/40/50/60 w/o any DMG increase.
And it no longer applies the healing reduction effect.
Sorry for any broken language.
Hope you have a good game! xD