IMHO -- Joan will survive. She's a major character on the show, and they will bring her back, injured or not. UNLESS - Wendy wants to re-negotiate her contract and things aren't going well.
I hope Jeremy lost his nerve at the last minute and shot at something else (not himself). This is a good chance to have the writers deal with the real problem of PTSD. Denise and Frank have been through enough. Killing off Jeremy would be an "oh, c'mon!" moment for me. Let's let something good happen to this boy!
Don't know about Pamela and Chase. She left in a hurry. I think she just wanted to get away with the kids after finding out Chase chose the special training over them. But hey - that's military life. Not many guys turn down those special "offers"!
Roxy and Trevor - they'll eventually take the hump bar off the "off-limits" list. Trevor is really trying hard in his recruiting role, but how much longer can the writers focus on this? They already have this season.
Lenore - or Leni - is back to stir up trouble. They will draw this out. Fort Marshall can't close, or there goes the solidarity of the show! Somehow the General (Michael Nouri) will figure prominently in next season's episodes - just so his wife can! It probably won't be easy for Michael and Claudia Joy.
Something will happen with Roland's doctor friend. I think they'll prove he was innocent of the charges. Wonder what that actor is doing now?
Roxy's friend will come back to help her. She's too strong a character.