A better ranked system that should be in place
So with the current ranked system in NA low elo is a fiesta. You need to change the way the ranked programs work to give players more fair games. The problem is this you have 27 ranks between bronze 5 and challenger/masters (25 ranks to D1). In 10 ranks, bronze 5 to silver 1, you have 70% of the ranked player base. Then you have 30% for 17 ranks. Assuming you did even distribution for the ranks as the player base sits Bronze 5 to Silver 1 = 7% of players, then from gold 1 to challenger is 1.7% of players. The odds of getting someone who is having a bad game or just unskilled for the division is much higher in low elo. A more even distribution of players among the ranks needs to occur to plat 1. This gives low elo players less of a chance of a landslide game with more balanced teams.
The player pool you should pull from is starting with your division, then go to the next rank up/down to get the top/bottom from there based of LP. Pulling players from an MMR based system doesn't make sense because your rank is based off wins and losses. An example of this was on a stream of a D1 player he got matched with a D5 player who was on a 4 game win streak with over 20 kills in those games (probly got super lucky to get fed). In the game he played you could see he was clearly mechanically outmatched. If you put a D2 player in his place the skill gap should be much less and again games should be closer.