One buff idea, and one silly idea for Plague
What if she could corrupt her own fountains? Similar to Oni, in that every time she M1s a survivor, she collects blood/power/filth/red wine, she charges her incense holder. Once full, she can corrupt a fountain herself. At least in this way, she isn't totally beholden to survivors cleansing, or at least cleansing in the far reaches of the map. Still needs to go smack survivors about, but at least she can use her power more often.
To go further, what if she could teleport to corrupted fountains? She'd have to interact with a fountain, of course, and doing so would cleanse the fountain she teleported too, but it 'could' give her some map control.
Comments
Teleportation would be interesting on plague but since she already has great snowball and can injure map wide I wouldn’t go with it.
As for corrupting her own fountain it could work. Plague is rendered an M1 killer if they refuse to cleanse but that’s what your base fountain/ apples are for.
She’s fine right now imo