Back in ye olde day the druid forms were forced to be the classics because giving wacky forms wasn't even considered outside the travel forms, and was bound by the lore of the Worgen getting exact Nelf copies of Cenarion teachings (forget the lore for the Darkspear).
As SL customizations show, Blizz acknowledges that players don't really care about lore restrictions anymore. So we could get Dwarf and Belf druids and there wouldn't NEED to be lore for it, although they usually do at least a little (see the fuck all Prelate lore in Zandalar even though its the de facto special class for Zandalari, and the HUUUUUUGE amount of Kul Tiran shaman lore in Stormsong Valley)