Is it bad form to go cloth?
I'm kind of a fan of from the Halls of Stone questline.
In 5 mans and heroics, it is fairly difficult to find a decent healing set that is full leather. As long as you are not taking cloth from a cloth-only class, I would assume that since a lot of the cloth pieces have the itemization that Resto druids need, you will be fine. Just remember that the mage, warlock, or priest in your group may get frustrated if you roll on a lower armor proficiency.
When you move into 10-25 man raids, it is best to just get leather. At this content, leather gear that druids need is abundant, and you will have no problem getting a set.