Lock the 'Play' button in the client until the Patch Notes have been clicked
Another champ, another random who has no idea that the big cheese everyone has been talking about for the last, what, three weeks, has a really long range ult.
I see this all too often. People queue up without reading the patch notes (and this was a big hitter during the preseason) and their jaws drop into the basement when they hear that Graves now has a new Q and different auto attacks.
Which is why I suggest a teensy tiny change to the client (or the patcher, if you want) that would lock the Play button and grey it out until the suggested link leading to the newest Patch Notes (or Champion Spotlights, even, if necessary) has been clicked once. It'd open up a new tab/window in your browser and at least suggest the player to take a look before they hop into the game so they at least have a general idea of what's coming for them.
Games are fast-paced. I have neither the good will nor the patience to explain to a random teammate in the middle of the laning phase exactly everything the new Champion can and can not do, what his strengths are and which abilities are most likely to take you from behind harder than a prostate exam conducted by a train.