I would love to have seen the development of a real romantic relationship between Cordy and Angel. And I think a Spike/Cordy friendship would have been brilliant; I love their brief interactions in "You're Welcome," (if you can call them "interactions.") There'd have been lots of bickering, but lots of respect for one another. The two of them have a similar way of seeing the world when all is said and done, and they'd keep each other in line.
I loved the chemistry among Cordy/Gunn/Wesley, and I think after all they'd been through she would take on a bit of a motherly role in the group.
As for getting her out of the coma: I'd like to think that the PTB would decide that she wasn't ready to go; that she could still do plenty of good by Angel's side, and that she deserved to carry out her life as she wanted. They'd also realize that she was a fantastic companion for Angel, (whether romantically or not), which would be further motivation for keeping her on Earth. So they'd be the ones to end her coma. But seriously, I haven't thought it through at all! This is just off the top of my head.