Correct me if I'm wrong...(yet another Team Builder/new champ select topic)
Isn't all of this just a work in progress? I've been assuming that Riot knocked out Team Builder in part because it was never meant to be a permanent solution, but also to get a larger sample of data immediately after unveiling the new champ select. I believe they plan on replacing Blind Pick eventually with something more like Team Builder (except better), allowing flexible players to either go with the current system or Fill in whatever the next Team Builder is called, and then funneling all of the one trick ponies into that mode as well.
If getting rid of Team Builder now gets us to that place sooner then I'm all for it. A lack of fill option (because filling in blind pick doesn't mean your team won't still be a toxic mess) and the inability to change champs because of team comp are the only significant flaws I found with Team Builder, and if a newer version of it eventually replaces Blind Pick then queue times should be reasonably quick as well.
Just saying.