It's the combination. The control spells matter because each time a foe enters or leaves PAM's reach for the first time in a round, they give the party some tempo. If no PC can close, the control spells become inefficient. When fear wears off, the foe attacks and now the wizard has one fewer spell slots. If the players would commit to all-warlock or all-CEX/SS fighters, they could probably find combinations more optimal. But generally - working together - three archers and a tank is flexible and strong.