Where does this game fit into the story?

I used to love these games and the second one was pure class. But from there on out its been a huge disappointment and I barely made it through the 'expansions' of the second one and stopped mid through the 3rd one.

Then I hear the 4th one would be mostly around ships? How has that worked out? I hated that part of the 3rd one so I didnt bother with it.

Then there is this one that I have heard nothing but complaints about!