They way I see it though is Shanks had a bigger impact with the show being good in the first place. The Jack and Daniel friendship was big part of the shows success and basically the chemistry between the whole team. I think if he wants to explore other chances that seems fine just like Anderson wanting to work less. They kind of earned the chance to maybe do something more personal after they contributed so much and then with Jonas it's not like they couldn't still bring him back or even transfer him to Atlantis. Their is that and I seem to recall back in the day their might have even been behind the scenes issues with Nemac because he was a scientoligst or something. I might be confusing that with Tom Cruise though on "War of the Worlds" were people were talking about him trying to brainwash Dakota Fanning. This was when people were really down on Cruise after the couch jumping, thearpy insulting stuff.
Jason
Jason