Why doesn't league have an report option for pre-game lobby already?
There are a good number of issues with the idea of a pre-game lobby report feature, and most of them boil down to "It's pre-game lobby".
For example; the biggest hurdle to overcome is the fact that, during Champion Select, anyone can opt to bail out (queue dodge) at any time before the match actually begins. This alone creates a big problem for the idea of pre-game lobby reporting since, if it were implemented, then you'd likely have cases of players queue-dodging immediately after spouting toxicity to avoid punishment.
Second, there's the issue of when the punishment is effective for pre-game lobby toxicity. Should it take effect at the start of the match? And, if so, how do you handle ZT chat, since hate speech and encouraging self-harm warrant a temporary suspension on the first verified offense? Would they still be allowed to play the match out, or would you have the match be 4v5, etc?
And I already know one option that's sure to be proposed for the above question; "Kick the player, apply the punishment, and return the other 9 players to the queue to restart the lobby". This, I think, is a recipe for disaster. Not only for the way it carries the slippery slope effect (starting with pre-game lobby reports, then people want the freedom to dodge/restart the lobby if a report goes through...), but also because you run into another problem; queue times.
I've seen a lot of people boast that they'd gladly accept longer queue times in exchange for game quality, but, when it comes down to it, they probably have a lower tolerance for queue times than they say they do. After all, if you're queuing up for League, odds are high that you want to play the game and not just sit in queue for as long as a match could go - if you could even get into one.
And on top of all that, you have to worry about abuse cases. If the punishment/queue return idea is what you go with, you have to both prevent abuse by premades (which is effectively simple enough, since you could cover all members of a premade group so that they can't try to "fix" their odds of winning), and prevent general player abuse, I.E., instigation/baiting. If someone can all but guarantee a safe exit from a team they don't feel good about just by ruffling feathers, you can bet that there'll be plenty of people out there who'd jump on the opportunity.
At the end of the day, there are a few too many fundamental problems with the pre-game lobby that make pre-game reports an infeasible idea, not the least of which being the obvious that the game effectively doesn't exist and never existed if anyone decides to queue dodge.
