Re Island Sanctuary, Yoshi has said there will be updates and additional content going forward, I would imagine it will be tied to patch content as it is released.

Story content: as far as I am aware, we DO have new content for Aglaia coming. AFAIK Pandeamonium is done, if there is new content for that storyline, I havent heard anything. The arc may be completed.

Glamour is an ongoing issue, I am sure they are looking at it as they are with a great deal of other factors, so all we can do is wait.