Im going to say world builder.  I got a lot of content waiting, but really if you want to allow for more powerful gear it could wait for that since there's probably enough gear atm.  Also inventory upgrades so we can hold more items.  Just so you know I've got 4 whole sets in the system with one of them ready to be released.  other three can probably wait but they have graphics at least.

I would suggest wood cutting also.