No, its not a giant alienage. As the elves wouldn't be minimized in society and the areas they live in would be maintained. Hey, the pro elves are just as in favor of further isolation in wanting elven countries.
It is an Alienage though. Sure, it'll be as nice and clean as the elves make it, but it shares the same purpose, which is to spare humans from the utter insult of having elves exist within their proximity. And yes, I find it very amusing that the "pro-elves" think this is actually a good thing.
On the 2nd part you take just the same risk if you have an independent country. A small dalish country will only be independent until Orlais decides to take it back by your argument.
Right, because that's exactly my argument. An independent, racially homogenous country (especially if its carved from land that people are currently living on) solves nothing.
At least this way it would still be part of Orlais, and Orlais would still benefit from it.
How does Orlais benefit from it? In short-sighted sense that they have a new place where the elves can **** off to and not be a bother for the human population?
Do you think they'll still be smiling when they're drowning in elven immigrants pouring in from other countries?