In a recent blog post, Mistwalker head Hironobu Sakaguchi wrote, "I am working hard on a new project. Now we just started going into the final phase of the production. No matter what, I will make it really good...."
A recently added page on the Mistwalker official site shows an artist by the name of Watanabe hard at work at his desk. What's that on the screen? A grassy field and perhaps a character? It's hard to say because the drawing is incomplete.