Im not sure that the voice comm would do the trick.
The bigger issue is that the premade teams has very balanced teams with real good healers, while PUG often dont have healers at all. And the heals are just outta the roof in this game, theres NO limits at all for heals. Players go from 0,5 to 100% Health in 1 sec if a few healers focus on that guy. And killing the healers in a premade Group is also almost impossible for a PUG team if its a scoundrel guarded by tanks and dps.
Its a huge issue and it needs urgetn attention or the game will keep losing players.