MF ult on the right team can be incredibly strong - the problem is positioning - having a frontline who can aoe control - and ironically given her passive: mobility. MF is just too immobile to compete against the ADCs that can dodge (or block) hooks - Kalista / Lucian / Caitlyn / Vayne / Sivir / Tristana / Kennen.
Really MF needs a more tactical Strut - something she can better use in combat, even with the new combat reset on Strut. Draven by comparison, has similarly brutal trading capability to MF (though I wish she still had Grievous Wounds) - but he also has a combat sprint, CC (knock-sideways), and an ult that has longer range and doesn't require him to stand still.
Draven is like MF but better in every way, essentially, and even he isn't really meta right now: she could use a bit of a buff.
With that said, Tahm+MF or Braum+MF are still strong bot lane combos (even if there are better ones out there).