Sometimes when people get stuck in conflicting agendas and positions, someone calls for more input from other people. If more input means more opinions, grievances or "ideas" it might not add value to the process and can actually increase the stuckness.
If anyone else is included, what helps are people who can assist with identifying more new questions, researching open questions and assessing the benefits and disadvantages of contradictory options.
More voices don't necessarily make groups smarter, only voices that bring to the table the right things at the right time.