What's the flavor behind this being in red? (As opposed to black, I guess. Not that I understand the flavor there.)

And any real need for it to be able to remove counters from players? That would seem to go against MaRo's desire that there be no modern cards capable of directly removing poison counters. Plus, getting rid of "player" let's you just say "permanent".

Hm. I was thinking something similar, but I don't know if wizards will start printing "damage to target permanent" or not -- currently I think they don't, but it would be a good way of letting things damage planeswalkers without saying "planeswalker" on them (which they prefer to avoid IIRC), and I think most people would understand that there was no point playing a damage spell on a non-damageable permanent.

My thought was that yes, the "player" clause allows poison counters to be "cured". It's a narrow use though; you'd either be doing it for political reasons in a group game or finding a way to hit yourself, so maybe it just goes away. Probably does.

Red was the right fit to me as it's basically stripping away anything but the "raw" base without counters, rather than just trying to kill stuff. Yeah, sometimes it'll kill stuff, but the flavor goal for me was a crazed former army medic that "cured" things — though not always in the most ideal way. More of a deluded incompetence than a truly malicious intent. In that regard, it might have been flavorful to have made him a goblin, but I didn't think it made sense to have had a goblin serving as a Debronian army medic (relatively critical story element).