In Wintertusk you will get to meet Grandmother Raven who will offer you help on your new adventures.
High level quest pets will help in your adventures.
An exciting enhancement will be the opportunity to enhance a spell! So Legendary wizards can grow in strength. Here's a quote from the producer's letter:
"Balance Wizards, we found some ancient and powerful magic to provide you a new, shiny, and more powerful healing over time spell! Storm Wizards, you’ll find some awesome damage at your disposal, but with great capability comes great danger."
There's also talk of a new arena with prizes?
Crab alley will be extended and the Selena Gomez quest line may continue or so it seems.
Those updates sound awesome! I'll try to keep you posted on what I hear about the new spells!