My experience in Competitive Mode starting in Season 7 changed dramatically -- for the worse. Based on some of the feedback I've read here and elsewhere, I know I'm not the only person to be experiencing this phenomenon.
In every comp season prior I have placed in low Gold (2000-2500) and stayed there throughout the season. This is true when solo-ing and in group play. This past season was different, though. I placed the same (something like 2020) and immediately TANKED. Game after game I encountered similar experiences: people playing the same offense character on Attack/Defense, or "smurfs" playing Widow or Hanzo and single-handedly owning the entire map. In both cases, the poor behavior came from very low-level accounts (either because they just got the game during or after a free weekend and haven't yet learned that countering is more important than k:d, or they bought a second account to purposefully exploit low-level matchmaking).
Over the course of Season 7 I dove from 2000+ all the way down to 1400-1500. I radically changed how I played by encouraging others into voice, exclusively filling with Rein or Mercy, and doing my damn best to work my way all the way back up to 2004 within the last couple hours of the season.
This season I started back in Gold and I've already been seeing a lot of the same problems. Just yesterday I had a game with a mix of Golds & Silvers, and one player (with no stars yet somehow ranked Gold) was exclusively playing Soldier and repeatedly diving headlong into packs of 4 or more enemies. Everyone on the team was practically begging him to stop, to change, to just try to stay alive, and he responds "Chill guys I just got this game like 4 days ago, I don't know how to play yet"
Please, please, please raise the minimum Comp level to at least 100. Make players put in some hours before they go into competitive games. Or at least implement some restriction on the difference between the highest and lowest level players. I do not want to be paired with people who don't know how to play and got lucky with placement, or are purposefully exploiting their low-level status. I'll wait 5 minutes to join a comp game if it means NEVER playing with either of these groups.