I Have lately been having same issue, but my problem is riot cant say its my no when i can lunch other games surf the web watch vids, all while there client is saying dc. also since the lunch of new client I also notice every game has one dc'ed person, and for worst ppl now dc @ loading screen, which if your playing ranked and some one dont load in they instant remake. For more that 1 to 3 mins gets that person 5 ban.
To the top of this the old client allowed you to disable peer to peer, there is no mention or visible sign of this on new client.
To less troubling issues been having this all throughout the new client (yes riot and you know this ) loot and store menus have a big where they dont open at time, people do care about this, just not as much as playing.
Further more I been off playing other stuff the last 2 months recently start back laying and off hand i notice almost every time i lunch the client ( not all the time tho, but a far # of times ) my net speed drops. and i know this because of pass experience with random dc in league, i always check my net status, and there is some times a clear visual of my net speed dropping, and i know thats peer to peer.
I can also clearly say its LOL cause on my game days i play all day and coming from 1 or 2 other games to play LOL and all of a sudden my speeds decline or be come unstable, (from over 16hr of one game to LOL and this what is this ).