Oh, I'm quite known for my dislike for his arc and here's my take on how they should have handled his arc:

I think that at some point, he should have realized that going back to Emma was a way to cop with Tamara's betrayal, honestly, that woman he loved was what made his character so loveable, it truly gave him great development, he grew up as a man and he decided to bring her with him and show him his past and his life, I think it was everything he couldn't have done with Emma and everything he did wrong before, that was amazing. He loved Tamara and stood up for her in front of his father.

Yes Tamara was a fake, but still, his love for her was real and unlike Emma, it wasn't something coming from fake memories, it was real and the product of Neal commitment to a woman, he had no doubt with her.

So I would have had him facing his grief and his scar, how much he was hurt and how his father killing Tamara hurt him, opening the door for the "I killed your mom" issue,. I think Neal shouldn't have forgiven his dad so easily, I think he should have been furious at him, because even though he was betrayed by the woman he loved, she still was the woman he loved.

I would have had Belle as a mediator between the two men, and instead of having Belle telling him about true love with Emma, I would have had her as someone telling him you need to deal with your loss and not rush things, instead of telling him things he wanted to hear, aka Emma is your true love, I would have Belle telling him, take your time to figure yourself out, you have two identities, Bae and Neal, accept them both, and then you will be able think of love.

I would have had him getting to know Regina, and it is no mystery that I would have loved Neal and her to be something, I think together they could make a lot of sense, and I think they could become great friends if not lovers. They could start bonding because of Henry, and then become friends. 

Neal's forgiveness could come the moment his dad dies for him, to protect him and Belle from Pan. And going back to the EF, Neal and Regina could deal together with the loss of their son, and when comes the time they try to go back to Emma, the truth about what he did to her has to be revealed, he almost gets punched by Charming, but then he truly tells them he is sorry and all he wants is to be a father to Henry.

When Henry and Emma come back, Neal apologizes to Emma and tells them he only wants to make things work for Henry and hope she will forgive him and be able to be friend with him. He tells her that if she needs to talk about Walsh, he will gladly help her, as a friend.

When comes time to talk to Henry, he tells him the truth, and tells him he is sorry and wished he had done things differently, that all he wants no is to be a father to him. 

sisterhoods?

Remember, Li Shang believed with "A Girl Worth Fighting For" versus Neal's "I'm never gonna stop fighting for you?"