So my group had decided that you can in fact allow the Weird Word to be directed all at one opponent, that's not what made it imbalanced.
What made it imbalanced was the bard in question's (Brd 14) ability to use their move action to begin inspire courage, then drop Heroic Finale to get a standard action and use the Weird Word again on that same enemy. Really bothered the DM that the BBEG was one shot by that.
