I feel you with this. It's a lot of smurf accounts that are set to unlock only the good champs in ARAM to win more. Wish it would also match you with players who also have around the same amount of champs. Then normal players would be match together and smurfs matched together.
I also get tired with the enemy team always have a better team/comp. See it just about every game, which has made me question the matching they use in ARAM. Seems less random for opponents then my team.
Sometimes you win, sometimes you don't, but more light shed on how ARAM's are setup/calculated would be nice.