I think, personally, this is going in a good direction for the elves. The Dalish have, admittedly, been living on unclear history for a long time. Whether or not they'll be proud of that history once they finally learn of it is another thing but they've proved throughout the series that they can definitely be arrogant and to an extent xenophobic. Solas seems to hint in dialogue that putting the elves back the way they were, is not the right course of action. While the Dalish have been viewed and view themselves as victims, to a certain degree, Solas points out that elves were not the romanticised peoples that everyone seems to want to remember. That they destroyed Arthalan through war, that they kept slaves, that the gods were actually nobles and that they could be ruthless.
I'm trying to express myself here but it's not working properly. Basically, the elves are the only race in Thedas for which the ancient version of them, the immortal elves, were thought to no longer exist, having been largely bred out of existence by human involvement or destroyed by themselves after the removal of their gods for guidance. This is a development I'm actually interested in seeing occur. I want to get a final word on elven history in Thedas and once and for all have the Dalish elves, trying to cling to that history, actually have an accurate one to reflect upon and see how true knowledge of their past effects them as a people.
As far as limiting the number of mages, I'll agree with what's said above. I can't think of a clan we've come up against that has more than 3 mages in it. I suppose this would make sense if it was an unconscious effort to avoid the mistakes of the past where so many elvish people were magic users and that this possibly attributed to their attitudes and their history. Afterall, Tevinter has proven what happens to a society when magic users rule. While not all of them are bad, there are more than enough to ensure that they make all the rules and have all the power.