Because this is is full of bugs. Lately my client sends me out of champ select by itself and the client doesn't load properly from time to time. This is extremely annoying, especially because it has been like this for months now. And it is not because of my internet because it works properly.
You promised us a better client, but in my opinion it is not better now. I don't want to end up with a leaverbuster only because your client is bugged or broken or whatever.