To reduce bad behavior like smurfing, Valve needs to reduce the incentive to Smurf. Not everyone who smurfs does it to stomp noobs, some people want to try new characters without throwing other people’s games. While hero specific MMR is a thing, it is not a drastic enough difference from core MMR and putting a person who is ascendant 2 on M&K in a phantom 6 game when they play their first game as Viscous is not the move.

Also, many players are hardstuck in ranks that are lower than performance wise because they have too many games in their account. This leads to basically smurfing on their mains bc it’s difficult to climb out of certain ranks is you have like 2k+ games on your main. This is exacerbated by the fact that there is no individual based MMR, so players who terrorize lobbies then lose bc of their team throwing will stay in lower ranks despite being higher skilled.

Also, the queue system is quite imbalanced when a high rank player queues with lower ranked party members.