Suggestion: Why not "merge" TB & new Queue
If the whole dynamic queue (and overall development) is sort of moving toward "pre-built" teams, why not use the "TEAM Builder" system to change the way the queues work.
If people want to play (what is currently) Draft or Ranked, they go to an interface like the previous teambuilder, you pick a role and a champion and once you open it up other people are slotted into whatever roles remain (based on their selections, people should have a "fill" option). Once you have a full "team", your comp is dropped into the "Ban phase" of the existing queue. This way, people can talk to their team BEFORE its in "Queue Phase" and players can look for another team if the current one is not a good "fit". I realize veteran players may not like this as too "convenient" for newer players (when older players had to suffer through toxic, terrible players to get to where they are). But if there's a way to reduce the bickering between players on a team BEFORE they get to the "actual" champ selection portion, why not make use of it?