I always keep a Druid in my party, only I don't use the black potions on my party at all. Instead, I mix up the black potions to sell off; I always also have a Cleric in my party, so having a GM Merchant really rakes in the money! (Cha-CHING!)
On the Light path, the Druid actually does fairly decent in melee battle (MASTER dagger!) As well as magic attacks -- they can Master all magics except light and dark. On the other hand, Druids can only possess basic bow knowledge, so ranged attacks really aren't their strong point, unless they use magic.
Also, the familiar on the dark side really isn't all that remarkable; seems like it provides a bonus to promoted Druids' stats, but it requires an extra day of food when resting. Unlike in VIII, where (If memory serves -- been too long since I played VIII) dragon hirelings enable the party to fly, this one doesn't even provide you with that.