I don't know what happened, but ever since Season 6 rolled out the matchmaking became so bad the game is almost unplayable for me.
Whenever I queue up in a random gamemode, whether it is dominion (very high activity btw) or a duel, the region, player skill and player reputation matchmaking settings always switches to 'all'. This is followed by another 10 minutes of waiting before I am put into a game with people who have 100 reps above me or people who literally just got the game. I am rep 26 and should not be matched up with people at these levels.
If I am lucky I might find a game within a reasonable time, however, the game is usually full of bots. I might as well just play bot games and skip the waiting time. It is almost as if I am the only person left that still plays this game.