Well it depends. When I played my druid in AD&D wild shape was primarily a utility for sneaking about unnoticed or accessing flight or swimming (or even burrowing, gogo mole form). The focus was on control and leader spells. Druids have excellent control spells both as AoE damage and as spells that restrain. Their healing is decent as well.
In 3.5 and on, animal summoning, wild shapes, and animal companions did become the bigger deal. Wild shape and animal companions are mainly used to act as a striker, though some of the larger forms can be excellent as defenders, and so can a veritable swarm of summoned animals.
So I see the druid as someone who has strong thematic ties to every class role, which makes it quite hard to design one. Personally I was considering that you could simply tie the roles to different abilities in the same class and provide a class with about 5-6 powers per level divided between wild shape focus (Strength and Dexterity or Constitution) and caster focus (Wisdom and Charisma (once upon a time you needed Cha 15 to even become a druid).