|B.A. Ironskull Star Voter 2013, Star Voter 2014|
Without spoiling the AP and to echo Aido's post, it seems like creating tactics for some caster enemies that include Will saves for the tanks will force the bard and cleric into a tough spot, depending on where you are in the AP.
As a GM, you should feel free to alter an AP or module to appropriately challenge your players. Nothing is scarier than having one (or two) of a party's big damage-dealers taken out by suggestion or a similar spell.
It might sound cheap, but this will ramp up the action for the party when they are forced to abandon the smash-kill-heal-repeat cycle and also allow for the support cast to play a larger role here and there