The count down timer skips. It's like it isn't in sync with the server. 3 or 4 ticks will ding off in rapid succession. Usually occurs on the countdown after champ select and before the game loads.
While in game, the client will "catch up". A number of actions will appear to fast forward (redraw of map, minion movements, caster animations). Sound is usually way behind the "catch up" portion.
Unable to start a chat discussion while in champ select. You must rely on your friends initiating a conversation
Unable to see your friends list while in champ select.
Must run client in windowed mode, it wasn't always this way.
Unable to change summoner spells or change masteries in the last three seconds of the count down before the match starts. Might be part of the catch up issue.
Unable to change skins during champ select. Must wait until after.
The loading screen for a match takes an extremely long time to render. It was always sluggish, now there is a 15-25 second delay before it actually shows a champion. There is about 5-10 second delay before it actually loads with empty frames.
When a game fails to load, the client doesn't go into bizarro land anymore requiring a restart. However, it does seem to happen more. Is that so you can show off the fault tolerant feature?
I was told that coffee and cookies would be served when you receive a chest. I haven't gotten mine (I like chocolate chip and black coffee, please).
The client's heuristic engine still does not identify players that actually wanted to play bot games and allows them to queue into ranked matches.
The client still only allows me to ban 3 champions, when I clearly need to be able to ban 126. I need those bans because of the aforementioned heuristic engine issues.