Amongst the discussion of rootkits and anti-cheat, I would like to add that part of the reason it is necessary is caused by the game companies that took away the standard method of playing multiplayer -- players running their own servers. It used to be pretty easy to just ban people from playing, now we're 100% reliant on their ability to do it. So we have anti-cheat which roots our computer, and still doesn't 100% s…
The only actual problem with cheating is leaderboards. When you have accurate matchmaking, you will be playing against other players of a similar skill level. If you we're playing in single-player mode, it wouldn't bother you that some of the players were better than others. Whether the person you're playing against is as good as you because they have aim assist, while you have a 17g mouse and twitch reflexes shouldn…
You can't have accurate matchmaking and allow cheating. People cheat for a variety of reasons, at lot of cheaters are just online bullies that enjoy tormenting other players. In a low ELO lobbies, you would have cheaters that have top tier aim activated only if they lose too much, making the experience very inconsistent.
Top tier ELO would revolve around on how the server handle peeker advantage and which cheater as the fastest cheating software. It's an interesting technical challenge, but not a fun game. As soon as a non cheating player is in view of a cheating player, the non cheating player dies. That doesn't make for a fun game mechanic.