First off: KUDOS to everyone at TGW for keeping that a secret! That took everyone by surprise which is what shows used to be able to do before the internet. Very well done!
Secondly for all wondering Josh Charles was done with the show! We were lucky to get him back for a season 5 at all. I hope it's ok that I post this here. It's a link with an interview with Josh about Will's exit:
The Good Wife Exclusive: Josh Charles on the Shocking Twist
He was the only series regular not signed to a 6 year deal, which is standard when you are starting a new show. Instead they gave him a 4 year deal. After speaking with Julianna, with whom he's be friends for years, he decided that he'd come back for one more season but he decided on 15 episodes. Then the writers asked him to come back for one more in flashbacks and he agreed. Everyone associated with the show knew this was coming.
I liked the letter they posted on Facebook saying they could do this or "move him to Seattle" which was a reference to George Clooney's departure from ER when he and Julianna were playing such a happy couple. IMO they were right to do this. If the actor was done with the show, then sending him to prison as part of election investigation would not have worked nor would have moving him away. Nothing would ever be final between him and Alicia. This was final, and it's going to change the way the show is once again.
I will miss Will. I've been a fan of Josh's ever since Sports Night, but if he wasn't staying, then I support the decision to kill off Will. This is going to give the other actors so much good work. And if the writers are smart, they will grab Michael J Fox as a series regular since his show was canceled on NBC. I'm looking forward to seeing what they do with this.