I had no idea, that ... (spoilers)
Weir was coming back! Good thing I avoid spoilers! I read that Torri turned down the job to come back after reading a script. So I assumed she won't come back ever. So I was really surprised. The fact that she was played by a different actress made it even more exotic. I was very shocked and sad by the ending. But I like it when SGA turns dark. When Sheppard goes to the dark side.
To illustrate, how hot dark!Sheppard is: