Toxicity, easily. Because logically speaking, to get rid of toxicity, would mean to get rid of its causes in real life, including stuff like racism, sexism, homophobia, trabsphobia, xenophobia, etc. And that obviously has HUGE, TREMENDOUS knock-on effects in real-life.
Get rid of cheating? That's nice, but that only affects games themselves.
Get rid of toxicity? You're not only improving the game, but the world outside it as well.
Not picking "toxicity" would be incredibly short-sighted in that kind of way. Because even if you don't have to deal with it in-game, by getting rid of it, you'd be improving the world outside the game as well, and to pass that up for something that only affects games themselves... I just don't get that at all.
And all the people saying "I can just mute people" or whatever... That's nice, but it doesn't always end there. Sometimes, that's only the beginning, and it only gets more nasty from there. Of course, I'm talking about stuff like this:
An Ohio video gamer who played a role in a hoax phone call that led police to kill a man in Kansas was sentenced Friday to 15 months in prison, authorities said.
www.cnn.com
Simply buying someone ain't going to fix anything like that.
And for those that can't see the article or it's not working for whatever reason, that's about a SWATing incident directly related to online gaming.
Of course, to be clear, I've fortunately never been swatted, nor have most people. And that much is obviously a good thing.
However, the point being that it nonetheless does happen, and that simply muting someone or blocking them is not some instant cure-all to toxicity.
Cheating can indeed ruin games and make them unfun.
Toxicity on the other hand, can flat out end lives period.
So if I actually had the power to do either of those things, toxicity, easily.
Because I don't have to have a SWAT team personally called on me over an online gaming session to have sympathy for those who have had to endure garbage like that, no one should have to personally endure it to have sympathy for people like that, and I'd gladly endure cheating 1000x over even if shit like that, if something that can easily lead to lives being lost, can be stopped instead.
Toxicity easily, and shame on anyone who says otherwise, because stopping cheating is in no way more important than what you could do instead with that kinda power, if it were real.