I
never said they can't make something up, I am saying that so far nothing fits. That is my point of view. Take it easy.

I do wish to speak more on the matter though, and mean to say the following in a gentle manner:
Worgen have the benefit of being a brand new race and while I don't agree with them being druids I know Blizzard will make something up. Druids could potentially have some link to the Worgen and their homeworld or maybe they're responsible for the Worgen somehow, who knows. Trolls on the other hand have been playable for years with no hints to druidic ties. Based on in game experiences of questing for them and killing them they do not seem like candidates for a druidic race to me. I haven't read anything at all on Trolls that supports a desire to maintain the balance of life in the world. Trolls are even reputed to be bloodthirsty by nature.
If one wished to
read about the lifestyle of one of the oldest known Trolls in Zul'Drak they would see how brutal and violent they are. Being an ancient race didn't make them nice or caring.
The
Zandalar tribe in contrast, which is also very old, is more focused on recording their history and maintaining their religion. They don't get too involved with the world if they don't feel they need to.
The Twin Empires attempting to wipe out the Aqir would seem (to me) much out of a desire to protect themselves and defend their territories than out of a noble intent of saving the world.
My meaning when I speak of voodoo and shamanism are as practices of the race but not necessarily something practiced by every member. Being a priest still doesn't apply to being what a druid stands for. According to a
Troll priest definition comes the following:
The troll priesthoods are, much like the shamans and the witch doctors of the various troll tribes, spiritual advisers and caretakers. With trolls being naturally superstitious and spiritual, it allows the various troll priests to manipulate the spiritual energy of the world in order to either heal or harm their targets. The various energies that the troll priests draw can come from various sources, be it Loa spirits, voodoo magic or the target itself. Drawing upon these energies, the troll priests either mend or harm, depending on which blessing the spiritual entity bestows. Arguably, in World of Warcraft, troll priests can be considered witch doctors in a cultural perspective, in equal terms with the shamans.
Here is
the druid:
Druids are keepers of the world who walk the path of nature, following the wisdom of the Ancients and Cenarius, healing and nurturing the world. To a druid, nature is a delicate balance of actions, in which even the smallest imbalance can create storming turmoil from peaceful skies. Druids draw their power from this wild energy, using it to change their shapes and command the forces of nature.
While neither the Night Elves nor the Tauren have the most peaceful histories, nor are all members of those races "good", they both appear to have had the benefit of Cenarius' influence. So far nothing of that sort has come up with the Trolls or been hinted within their history. I do not mean to imply that I don't think Blizzard can make something up for Trolls, it does mean that I don't see how being a druid really suits the Troll race. Also, even though I felt Blizzard could invent something for the Worgen I didn't mean that I think becoming druids suited them either. They are savage beasts or infected humans, as it stands right now being druid doesn't fit them at all (to me). I hope that clears it up a little bit. :p