Well, it would definitely decrease the amount of lane stealing, but I don't think that it will completely stop it. You would queue up for a certain role, but Riot can't really "force" anyone to pick/play the role the specifically queue up for. One could always queue up for a role and then decide "hey I'm gonna play a different role instead."
I mean, Riot could definitely implement specific ways to report/punish players who do this, but it's not like the hardcore trolls still won't have the ability to do so.
But yes, I do believe that it Team Builder for ranked would definitely decrease the arguments over who goes where.