Whether Furbolg become an allied race or have an introductory event leading to them as a core race, it makes the most sense to have the Night Elves and Draenei being part of their recruitment to the Alliance.
I mentioned in my Ogre megathread the idea of pre-expansion events leading up to Ogres on the Horde and Furbolg on the Alliance. I wanted to go into a bit more detail with the Furbolg side here since I kinda mentioned it and have been thinking on the idea more and more since then.
If you weren’t around when Cataclysm launched, there were some pre-expansion events that were really exciting to do involving questlines and a bit raid-like event for max level players that involved the Darkspear Trolls assaulting the Echo Isles to get their home back, leading to Troll Druids being reintroduced when new race/class were added, and Gnomes assaulting Gnomeregan to…well, try and take back their home. It sorta still was kept as a dungeon.
Videos of the raid-like events are here:
The idea of these is the hype that would lead into new playable races, both of which are ones that have been requested and could go along with an old world (of Warcraft!) revamp, which is something being considered that I mentioned a few posts ago. Such events would be something anyone could join in and do and open races to everyone, of course.
For Furbolgs, I imagine there being multiple tribes that exist that face a sudden and new corruption. Maybe have them assault the remnants of Night Elf and Draenei areas heavily. Needless to say that newly corrupted Furbolg armies would be low on the list of fun, happy, and healthy activities for the Alliance and their footholds on Kalimdor.
The questline for it would involve having to research this corruption by the Alliance while somehow not trying to slaughter the Furbolgs. This plays into the Night Elves long being allies to the Furbolg and by saving their people instead of killing them, it plays into how they would know from previous events that the Furbolg are corrupted yet again.
Obviously such details would need to be fleshed out, but let’s say that there is a way to stop the corruption of the Kalimdor Furbolg tribes for good that is utilized and the enemy behind this whole kerfuffle is known and located. Then the big raid-like event for it would be an assault on the villain’s lair.
Of course the question would be whole would be the villain for it? What springs to mind could be a Satyr, possibly with groups of other Satyr and demons if it makes any sense. It sorta plays into the area and Satyr have relations with Night Elves that go as well as expired milk under the summer sun. It’s possible other ideas for such a villain could be put in also, but this is what comes to mind. Motivation for corrupting the Furbolgs would be to take advantage of the Night Elf situation and then work on taking over Kalimdor perhaps.
Finishing this event would lead to multiple Furbolg tribes now immune to the corruptions that previous plagued them, with a shiny invitation to the Alliance as a mutually beneficial to them and the Alliance. The Kalimdor tribes get protection and help from the Alliance while Night Elves get assistance with helping their own lands and more of a foothold on Kalimdor should a kerfuffle ever happen with the Horde again.
It feels like it works in many ways, and with multiple tribes of Furbolg that would help explain the different fur customization options, it parallels the Horde getting multiple tribes of Ogres as part of the playable faction. Not to mention both being allies to their respective factions since the old RTS days. It seems like a great combo to me, even if it may not be perfect with Ogres overshadowing whatever the Alliance would get…well, aside from the one race that shall not be named, of course.
Anyway, just an idea I wanted to float out. Those more knowledgeable in Furbolg lore could flesh the idea out better than I could. Still, it would make for a great in-game event that would be memorable. Not to mention the excitement of it leading to new playable races, of course.
Until then, I’ll keep dreaming of seeing Furbolg on the Alliance side of that character creation screen! 
–44 days until Blizzcon starts (Nov. 3rd)!–
-Playable Alliance Furbolgs are a bear necessity! 
