I sold a bunch of mats as well... (even sold some sword mats since wolfclaws don't seem to be coming). New content would definitely be nice and the next best thing would be to at least inform us approximately when the new content would be coming.
Sell only the mats that you can grind for. I made the mistake of selling my Wolf Claws and not I can get Sirius Sword and Staff plans and can not get them because they stopped dropping in the arena when I made level 110 (I think).
The opinions expressed on this post are my own as a player, not as a Moderator.