This kinda needs to happen
Matchmaking is way, way too lopsided with premades. Im currently bronze 2 (although i fell from s5 after a massive losing streak) and I consistently get put against platinum and gold tier players. How is that remotely fair? My suggestion would be to put a cap on how higher and lower a player's rank can be to be able to be matched with you. For example a bronze player should only be able to face up to gold 5 and a plat player should be restricted to gold+ regardless of premade parties.
Speaking of premades, a clause should be implemented so we keep the team oriented objective still balanced. If your premade consists of massive level separation, say a bronze and a plat duo , they should only be allowed to face teams where a premade has a member of equal tier as the plat they should not be placed with the lower rank taking priority as to whom they will face. IMO it should be swapped where the higher rank gets priority. The whole "learn fast or die" kind of deal.