If, for the sake of argument, the elves were to rise up and attempt to reclaim the Dales, I have a horrible feeling that the people who would principally suffer by it would not be the nobles who have been oppressing the elves for the last 900 years but the poor blighters we met in Masked Empire. These human villagers weren't even aware there was a civil war going on until people rode in and started demanding things from them. Then after they had taken what they wanted and rode off, Celene's supporters rode in a slaughtered them for helping the enemy, Gaspard. As the person telling this to Celene said, they didn't even know who Gaspard was.
Now if the elves were willing to play nice and agree not to harm people like these peasants, who have no particular loyalty to any human lord and would just like to be left alone, then they would likely get my support. If not, and offering them the opportunity of a homeland meant displacing or killing these people, then I wouldn't be so keen. Now some Dalish might be willing to co-exist but others would not.
I just can't get out of my mind the fact that when they fled over the Frostbacks to escape capture at the end of the War of the Dales, they massacred the first human barbarians they encountered because "humans can't be trusted". This story was recounted by the clan that gave us the Warden. Those barbarians had done them no harm and had actually probably been among those who had resisted Orlesian expansion in that direction. So if they had given them the chance, they could have been potential allies but instead they just slaughtered them. It seems to me that the elves will be no different to the humans in how they treat those weaker than themselves. I am actually very pro-elf but not at the expense of ordinary human commoners, probably because I come from peasant stock myself.