A big difference betwen the old ranked system and the new one that I havent heard anyone mention
With the old solo queue ranked system, pretty much everyone had a method in which they could play this game the way they wanted.
For the competitive scene, you could queue up as a solo player or a duo in the solo queue ladder and play that way. If you wanted to play as a 5 man team, you had ranked 5v5 to accommodate those players.
Sure, you couldn't queue up in a competitive manner as a 3 or 4 man team, but I feel that's a fair tradeoff for providing solo, duo, and 5 man teams a means to fairly play the game in a competitive way.
If you were really dead-set on playing as a 3 or 4 man team, you could always just do so in one of the non-ranked queues, which also allowed solo, duo, and 5 man teams to queue as well.
So with the system as it was before, everyone got to play with the team size they wanted to, but 3 and 4 man teams had no home in the competitive ladder. This was literally a system where almost everyone could play the game the way they wanted to, which however many people they wanted to, at any time.
The system as it is now completely and utterly leaves solo players out in the cold. There isn't a single queue that a solo player can jump into that provides them with a fair field of play anymore. Riot went from a system in which the VAST majority (imo, likely on the order of 95%+) of the player base had a "home" so to speak, to a system in which a HUGE portion of the player base is essentially just given the finger and subliminally told "you don't matter".
I would really love to hear from a Rioter about this, because its not something I recall ever seeing addressed before.