Once upon a time he had a grenade of some form, long before game released. Why not bring it back, make it say, rightclick. How about we make it a grenade that reinforces the tankbusting role and does let’s say, percentage health, with falloff. This makes it less oppressive but still dangerous for squishies to be hit by and makes tanks sit up and take notice, because suddenly their armor health is gone along with another significant portion of regular health and Reaper is on his way in. Also an option for this, give it a 2 second corrupted healing debuff. Where any incoming heal, instead of healing, is a little damage effect instead. Not quite offensive-use Ana 'nade but similar niche.
This may not be the real answer at all of course, but hey, what say you rabid lot. Tear into it, what’s good about the idea, what’s terrible about it, discuss!