Here's an interesting counter proposal. Make an arrangement with Orlais/Chantry to give a part of the Dales back to the elves but with the proviso that any human farmers already living there are permitted to stay and have a say in governing the place and that the elves continue to follow the Chant of Light. Orlais nominally still has sovereignty over it but within its borders they are pretty much self determining, raise and use their own taxes, etc. Orlais will stay out of their affairs provided they do not threaten the stability of that nation.
Then go to every Alienage and make the offer to their leaders, propose a form of government that gives everyone equal rights and ask them to canvass for volunteers to help set up this new state. Give them the resources they need to get started and support during the initial period, whether military or economic. Hopefully this will encourage these ex-city elves to work with their human neighbours and engage in trade and diplomatic relations rather than try and shut themselves off altogether.
For the sake of argument, let's assume our experiment is a success. Where does that leave the Dalish with their desire to recover the power of ancient Arlathen and their loyalty to the elven gods who have done precious little to assist them? Shartan wanted an elven homeland for his people not a new elven empire and that is what they get.
The arrangement would die the second the ruler of the moment decides its inconvenient. And if you are going to let the humans have a say on how the state is run, what's the point of creating it? Why not just give equal rights to elves? Oh, that's right. Humans are a bunch of morons who regard elves as little more than pretty animals. So yeah, lets get them mixed in, I'm sure it won't end up in a purge of the elves after the first douchecanoe human gets lynched...
The thing is, with the attitude humans have shown towards elves the only possible solution is an independent elven state where humans are NOT citizens. They might live there, but their status is whatever the state says it is. A bit of "shoe on the other foot" would do them good. Any situation where humans have any say in elven matters leads directly to the current situation.
The dale elves and city elves would probably get along just fine with city elves building settlements and the dale elves keeping to their hunter-gatherer lifestyle with people of both cultures being free to choose their way of life, as they already do in secret. With this kind of binary cultural division it would be logical to assume that you are also going to have two systems of government with a council of the two for settling disputes and for matters that concern the entire state.