Great thread idea! These aren't in any order, they're just as I think of them.
1) Josh Stone
I really liked Josh's character in RE5, especially when we saw a little more personality from him in Desperate Escape. We saw a little humour from him as well as a kind personality. I'd especially like to see a spin-off where he's paired with....
2) Sheva Alomar
This one is going to be unpopular, I can see it now.

I think Sheva was a strong personality, she wasn't afraid to challenge Chris about Jill and she had a sense of duty and justice. Plus, she had a fair bit of depth for one game. We learned about her back story, her thirst for revenge and also saw a more caring side to her throughout the game. It would be cool to see these two characters in another RE game.
3) Moira Burton
Moira was a breath of fresh air for me in Revelations 2. She was ballsy, she reacted how a lot of people would react in the situation she was put in (I'd be swearing like a sailor in that situation), and I liked her sarcasm. Plus again, I liked her kinder side that she displayed to Natalia, and how she came to care about Evgeny.
4) Natalia/Alex Wesker
I've lumped these two together because I want to know how Alex's consciousness will affect Natalia. I would like to see the struggle of Natalia fighting to stay the sweet girl she is whilst Alex's evil is trying to break free.
5) Sherry Birkin
I'd really like to see Sherry interract again in some way with Claire, or more with Leon. It would highlight the friendship they all share. She's also got a naiveness about her and it would be interesting to see how that would change, yet she's also got a weariness about her abilities.
6) Jack Krauser
Krauser was the definition of ruthless, he saw his infection as a gift and I think it would be cool to see him in some capacity again. (I know he's dead and to resurrect him would be a bad move, but I just wouldn't mind seeing more of his character).
7) Manuela Hidalgo
This is going to be another unpopular one, I imagine. Manuela is infected and it would be cool to see if this would affect her later in her life in any way. Maybe people could be after her to study or use her abilities. I would want her to stay helpless though, and play as a different main character who'd maybe have to protect her. I couldn't imagine her being an agent or anything like that.
8) Svetlana Belikova
Purely because she's cool, she's great with hand-to-hand combat and I've always wondered what was up with that scar on her back.
9) Jessica Sherawat or Raymond Vester
Only one or the other of these two, purely to find out what the deal was with those two at the end of Revelations. I didn't really care that much about their characters though.
10) The Merchant
Just for a laugh. 'Not enough cash... stranger....'. 'Is that all, stranger? Heh heh heh heh... Thank you'.
The last couple were a bit of a stretch just to fill up my ten. I'm sure a lot of people won't agree with my choices.
