Okay, so I've been really lapse in my Sanctuary watching and *GASP* OMG!HOLY!HANNA!THEYKILLEDOFFASHLEY?!?!?!?!?! WHA? WHY?! Is there a reason for the exit?!?! Somebody inform me! *cries*
Haha, when you said really lapse I thought a few eps, not like a whole season! :P
I think there's bits floating around the net but AT has said that we'll never know the real reason. However, she also said that she would love to have Emilie back and there was a storyline in place to bring her back if they got a S3. And since they got a longer S3... idk, I guess it depends on EU's schedule and mebbe some other PTB stuff.
It's cuz TPTB who aren't AT decided to pull a Russell T. Davies to piss off all the fans.
But the good news is the Emilie is on Riese! (However, they've had to take down their eps while they negotiate with Fireworks about rights and money and stuff *rolls eyes*)