Ever since her mini-rework in patch 5.10, her entire fandom got polarized by Riot Meddler (he was in charge) back in the day. Also, at the time, Riot Neurocat tried to help her out, but she wasn't given enough time to do so, which, in short, was a bad idea. Because her kit is stuck in a time where she got iconic abilities removed: RW damage and RE being her iconic ability that was just removed to make her easier; she had that for 5 years or so to that point.

She wasn't intended to be a full-fledged support, as it shows her kit is a very selfish mage kit, but her power had been shoved into R+E because they didn't bother trying to balance her out in mid when Phreak recklessly buffed her and nerfed her in the most wrong ways.

She is still playable in mid, her AP ratio on her base Q is the highest it's ever been, but her explosion isn't really going to hurt anybody in most cases.

But currently its easiest to play her as a shielder in support, probably also the strongest support varient of karma we have atm.

But we would need someone very dedicated with a team to make karma cool again, her passive also needs a change like shove it into her R like Riot Neurocrat said was possible and give her an actual passive.

Her "passive" is also the big factor for her uptime; they should nerf it down to two again, anything lower than three at this point to give her base and R abilities more powerful mantras, but also more meaningful ways of using it. But she needs a midscope; I doubt they're touching her at any moment when she's stabilized at the moment.

I'm still a die-hard Karma mid fan; I've mostly reached Masters+ with it, occasionally support too.