When you complete the “Legacy of Leyara” achievement, you will receive a mail from Theresa Barkskin containing a locket and another quest. Upon turning the quest in to Rabine Saturna, I received 8 gold 27 silver but also a message “you don’t meet the requirements for that quest.”
If you haven’t talked to Rabine Saturna about Dire Maul, talk to him. When done, the next quest will appear when you talk to him again – “Unlocking The Secrets Within” and you can continue the quest line. (There won’t be a question mark over him – just talk to him again.) If you’ve already spoken to him about Dire Maul, you may be able to get the quest to appear by grouping with someone who hasn’t and having them speak to him but I can’t say that for sure. Still, it’s worth a try.
It’s a short and easy questline, and at the end Malfurion gives you the locket – which transforms you into a Druid of the Flame – 1 hour cooldown applies.