I am guessing he may be too expensive given his SWAT success. After all that is the reason CBS has given for canceling so many highly rated successful long-term series. Maybe the odd cameo would work dollarwise but not sure on the storyline. But writers could easily make the other 2 character return options work as they have in the past.

Jim Parsons made occasional appearances mostly at the end of the prequel. But I think there are layers of grief in Gibbs we are slowly seeing surface in this very private man. Perhaps telling these stories behind the legendary character and his relationships will allow Gibbs to process his complex grief/PTSD and allow him to rest, relax in peace and have a happily ever after with new friends in Alaska. I still see him having bought that boat and writing these stories in his journal to tell his story and think about....the rules and his relationships.

Jane Tennent.....to redeem herself under the watchful eye of Leon Vance till team lead Parker is field ready.

I still think Sam and Some mbers left alone without a "home" after their series ended could form a new spin off ie NCIS: ELITE which was vaguely hinted at in the last season of NCIS: Hawaii.

All characters knew Gibbs and related to each other ing through the mothership so let's not totally get rid of some very finely crafted Characters! Will be intetesting to see what happens. I mean Leon could decide to retire....After suddenly striking a cord with his son or perhaps he too enters part of the family business ie CIA, or CID or Intelligence gathering of some sort. Would be great to see Kala in action more...which could happen with crossovers.

But Tenant would be under the watchful eye of NCIS director right in DC HQ as these storylines progress/resolve.

Sadly the problem with bringing NCIS Hawaii back is the actor who portrays Kai has already accepted a new role/gig. CBS made such a raft of bad decisions this spring canceling solid shows for no reason! Travesty after Travesty!