TFS is a winter destination only and the summer timetable kicks in just before Easter and therefore it is not available unfortunately. Whilst you're right in what you say everyone wants to go to TFS, but they also want to go to other places just as much.
I'm a little out of touch with what happens in NCL but I would imagine PMI will be back, GVA is staying year round, NCE and JER will be starting back up soon too as well as (I think) increased frequencies which is what the aircraft will be working.