I think that the Druids as an order were and are necessary. Alanon, now he was... well a bit like what the Ohmsfords accused him of. manipulating without explanation. I could realy Identify with the mistrust and the "What do you want now Alanon?" attitude.
Now I know that sounded a lot like a waffle there, I do think that Brooks' Druid were there as "keepers of the realm," so to speak. so in that sense they are a necessary part to the story.