Steel_Wind said:Because the iconic four are assumed by virtually every module designer, if you don't have them present in either PC or NPC form, you will certainly have to make changes.
Yes, the group knows what we need and tries to cover the bases. I'd consider it a must - though that does not mean it's a must from a player perspective. If the players are not going to do it, I try to fill in with either an NPC to fill the role or an item (for healing) which can mimmick the missing element.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.