"Fix Matchmaking"
Sooo... What part should they fix exactly?
In an ideal world, you are supposed to play with people from the same skill bracket. Isn't it doing this quite well already?
When players with similar skill compete versus each other they have 50% chance to win or lose the match. I assume most players have a winrate around 50% so this seems to be working as supposed. Everyone's MMR either drops or rises until they reach that 50% WR which means they have found their current deserved rank.
If you have 500 games, 50% WR and are stuck in gold 4 it's not because bad matchmaking. You have just reached your peak rank. Why can't people get this in their head? Only improvement in your own gameplay can make you climb again.
Now let's say matchmaking is indeed broken. If Riot magically repaired it, you would still have victorious teammates only half of the time. The other half they "int", "troll" or suck. Unless you are better than them you won't win any more than 50% even if the system was perfect.
I'm curious how do you want Riot to adjust the matchmaking. In my opinion it does its work right. No-one gets their rank by luck, it depends greatly on individual skill. And that's the point of ranked, right?