What if Ghost made champions invisible, but kept the particle FX visible?
The particle FX would act similarly to how the Sweeper's silhouette works, letting enemies know the rough location of the Ghost'er. For sneaky stealth plays though, the particle FX could be pushed out so it trails farther behind the Ghost'ed champion (by ~1s or so.)
Thoughts?
Edit: Ghost 'now' simultaneously grants +30% movement speed for 5s and, after a 2s fade time, grants invisibility for 3s.