What to expect from the second game?

I've played the first game a lot. Built several characters and made different choices. But I've never played the second game until now. I know it's functionally the same as the first, so I know what I'm doing in terms of playing, but I have no idea of the plot or characters besides a few names. I know there are some different classes besides the base Jedi class, but nothing about them.

Do I need any pointers as to which way to go (no spoilers please!) or is it better to just go in blind and hope for the best?