There are lots of good ideas here! Here are a few of mine:
Nicole comes clean to Eric and after a rocky time, he works through it and decides to stick with his decision to leave the priesthood. He remembers that he was trying to make the decision as if the proof had been found, and he decides he made the right one. That decision also brings him back to Nicole... they patch things up and eventually get married. Their story revolves, for a time, around their struggle to conceive a child. They eventually have happy, healthy twins! (Which I realize isn't new either, but... the story would give the actress that plays Nicole some emotional scenes that she is so good at, while being in a happy relationship, and will eventually have a happy outcome!)
Hope becomes worried that she hasn't heard from Bo again, and neither have John or anybody else. She gets a visit from the ISA (or whoever) that tells her that Bo was killed, but they were not able to recover his body. She grieves and eventually moves on... with an oddly comforting Aiden. Since he knows what she's going through, he puts aside their differences, and even her harsh words, to become the person that she goes to. This, of course, doesn't go over well with Ciara or Chase, so there can be lots of drama there. This also leaves open the option to bring Bo back ("the death was all part of the story... it had to seem real") after Hope and Aiden have moved on and the children have finally accepted their new family and become happy again. This will also bring about an opportunity to tell the story of Aiden's late wife and how she died.
Or, maybe... I hate to kill off this character, but whenever it is time for Caroline to pass (hopefully the actress just decides she's ready to retire and the show obliges), Hope and Aiden will be in their happy place, mourning the loss of Caroline. At the memorial/funeral/mass/whatever ceremony, a "dead" Bo shows up - either in hiding or in disguise - because he can't not say goodbye to his mom. And that's where he spots Hope and her new, happy family, which he now wants back, and has to choose between work and family.
Since John has come back, he has understood but been taken aback by Marlena's anger toward him. Since it is clear that she doesn't even want to look at him, he decides that he's really going to have to step things up to win her back. He doesn't do it in an underhanded way, and it is a slow buildup to an emotional reunion. Although he is so kind and charming and sincere, he has to endure many harsh words from those defending Marlena. But he eventually wins her back, the right way.
In the meantime, Brady truly hits rock bottom with Theresa. She returns to LA - her intentions unclear - while Brady finally decides to do what he needs to do to get clean. This eventually means making amends with his father. A new female character enters the picture. She is interested in Brady, but when she learns of his troubles, becomes very judgmental. Later we discover that she has also been down this road, and eventually helps him out of his troubles.
That's all I can think of for now. It's funny... I guess most of my ideas revolve around people ending up HAPPY!!