Whilst I'd love open borders everywhere, it'd cause a hell of a lot of economic problems. See: the USA's Gilded Age unemployment, current era globalization, etc.
The world economy's all sorts of messed up, giving people benefits for living in a certain area. Fix that, then you can fix immigration/emmigration.
I don't claim to know enough to be sure about anything, but the way I see it, is that a lot of the problems in the world are caused by people being stuck some place under unfortunate circumstances. Give people the ability to go where they want, and suddenly those governments out there who do bad things lose their base.
One way of looking at it is democracy where you cast your vote by choosing where you reside. Another, perhaps, is a free market approach to the situation. While I don't always like what these two systems provide for us as is, it certainly couldn't be worse than what we have now, where people are stuck in bad situations simply because they're too poor, or the borders are closed, or the barriers to entry of the more fortunate countries are extremely high.
Unlikely to happen anyway, and I'd be happy to hear better ideas. Like I said, I can't predict what ripples and waves this might cause, and it certainly would end up causing problems. At heart, I just don't like the idea that some people deserve better chances at a good life than others simply because of the circumstances of their birth. Also sorta pissed at the whole "not allowed to go to Cuba" thing, but that's neither here nor there.
Frumple was right, however, nothing will ever get done if everyone is waiting on everyone else to first fix their parts.