Love that you can add friend as well as block user from within the game.
However, currently you cannot use these features from inside the game if the game has finished - or if the person has quit (which is usually the point at which you decide that you never want to play them again). This seems a bit silly, as it is usually only once you have played through to the every end, and had a good experience, that you decide if you want to add someone.
It would be great if these functions still worked from inside the game after it has ended. I usually hang around for a few seconds and offer congrats to the victory etc afterwards, and it would be soo much easier to add people as friends then. Now, I still have to waste time going outside and searching them in the friends list to add them, when I could just click on their avatar in-game. Sure you can do this mid-game, but you are never sure of someone until you have played through without them quitting. I've had pleasant chats with people during a game, thinking I would add them as friends, only to have them quit just before I won. Obviously I no longer want to add them as a friend at that point.
Same with blocking. Unless someone is abusive in the chat, you usually don't know you want to block them until they quit with poor sportsmanship. At which point you can no longer use the block feature in the game.
The new features are a very big step in the right direction - and my game play has been far more pleasant since their creation (matchmaker also seems better too). However, they don't seem to have been fully thought out in terms of practicalities and work-flow during game rhythms.
Thanks for adding the feature though