Regina is a threat wherever they would go. Even if they figure out a way to keep Regina in one world while they go to another, there is no guarantee that it will last. As long as Regina doesn’t change or die (yup, that is an option, just saying, not saying she should die) it doesn’t matter where they go, they might find temporary relief but no happy ending.
As others said before, some decisions are in the end made for one. It’s not like Emma could really sit down, ponder all possibilities and reason all day long, which place might be better for her and Henry and family to stay, and where they would like to stay regardless whatever threats or neccessities excist. Regina is a threat, there is still Hook who quite sure will cause more mayhem, there are Greg and Tamara, and who knows who else will cause trouble. Emma hardly can take a breath.
That Emma is torn about which place to live doesn’t mean to me, that she will have really much of a choice in the end. But it would have been strange if she wouldn’t be torn about it. She did not just live most of her life in our world, she grew up here, as unhappy as it was for her in the foster system. And I don’t think that all is already fine with her and her parents, that the bonding is all done and no doubts there anymore, so as much as she wants to be with them I’m not sure it is enough yet to give all up on our world.
In the Enchanted Forest Emma would be a princess, the next queen. Some might find that very tempting but it comes with expectations and responsibilities, being a person people look up at and expect to handle a lot for them, being in the spotlight most of the time. If you want to be any good sovereign you can’t sit back because you have a bad hair day or just feel like it, you care, you act, you have to function no matter what. It can be very satisfying, giving you purpose and meaning in life, and it can be at the same time a burden. It can be a scary thought. Remember how Emma wanted to run when things got more serious than she liked it? That Emma is not all gone.
Think that this burden of expectations is something Snow feels and wishes sometimes to get out of it: be just someone, a teacher at primeray school, having a loving husband, kids, some pets, a household to take care of … no politics, no worries about bigger things than the next Sunday lunch and how her grandson will look in the school play. Someone who can make mistakes without risking the lives of everybody in the kingdom.
The Enchanted Forest as it is now is a zone ravaged by the Dark Curse. It’s not just the Ogres, it looked to me like a rather baren land, food hard to find, everything pretty much in ruins, no nice bathrooms, no hot and not even cold running water, no hospital anywhere close by, no supermarkets. This would be no camping adventure vacation, going back to the Enchanted Forest means pretty much to start from scratch. Oh, wait, there is magic, they could use that to rebuild in no time … but something gives me the feeling, they won’t, they can’t even. As I see it magic draws from the resources that are and works with them, and when there is not much left it might be not that helpful either, not enough to rebuild in short time. I still suspect that the Dark Curse didn’t just take the people away, it might have exhausted the magical realms. It might come back, magic and all, but it will take time (H and K might have a different take on this though).
On the other hand here in this world magic might have no place. They are aliens to our world, freaks, a sensation at best. As long as magic exists in Storybrooke they might be at risk, there will always be someone tempted to exploit it for better or for worse.
If Neal is any factor for Emma’s thoughts about where to live then more speaks for our world. Guess Neal considers any place good where there is no magic, any place where his father would be his father and not the Dark One, not being able to us magic at all.
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