Re: The question of another Pbem.

I know there is much controversy over the subject, but I personally prefer
2nd edition without skills and powers.
A campaign setting other than published puts all players on the same footing
in an unknown setting.
Of the options you listed I'd least prefer the political one, and most
prefer the exploration. As stated by others, preferably a smaller craft that
can be manned by the PC's without need to hire crewmen npc's.
I've also always liked the "secret agent" plot. "If you are caught we will
disavow any knowledge of you or your mission"