(Clarification): What I meant by the speculated storyline of other Night Elven settlements, making contact, exploring their culture, etc… was not to create a new culture but to essentially place a magnifying lense over the various aspects of what makes up the collective Night Elven culture.
(Speculation): For example, let’s say there is a militant settlement of Night Elves on some distant landmass. They fight as the sentinels, with the tactics of the sentinels, the skills of the sentinels, the armaments of the sentinels. They can easily join the existing Sentinels, but for us as players, we have an opportunity to see not only the varying ranks and chain of command and tactics on a far more intimate scale, but also reconnect to that savagery from WC3.
(Speculation): Then, maybe there’s another settlement of Night Elves, one that is primarily Druidic. They have their own sacred forest, something like Ashenvale or Val’sharrah, but on steroids. The Wild Gods they commune with and learn from are actively a part of their society and culture (this might even enable new Druid form options for Night Elves). We see how this group functions. More importantly, perhaps we see how their devotion to nature supersedes their concern for themselves. This could be a vital window of opportunity for characters like Tyrande and Malfurion to see how they themselves might have gone too far with the Cenarion Circle, and why characters like Leyara not only existed, but ever amassed the kind of following they had.
(Speculation): Then we see other settlements. Maybe there’s an underground society of Wardens who devote themselves to their view of justice, who have prisoners of various races on this other continent, who are seen as these jailers or the worst of the worst, and how their duty is sacred and inviolate to them. Maeiv encounters them with Tyrande, see’s their zeal and discipline and perhaps that they haven’t been compromised by their emotions. Maybe she decides to learn from them, and they in turn see the ultimate Warden and want to learn from her as well.
(Speculative): Maybe there’s a settlement of Highborne who basically have a society that focuses more on knowledge rather than power, and serve as advisors and councilors to various other settlements, collecting and storage knowledge in a vast library. It’d be a chance for Highborne among the Kaldorei to see a vital service they can provide their people, a way to better fit into society.
(Commentary): I do think it’s a chance to rebuild what has been lost by not only getting in touch with the roots of the Night Elves, but also expanding on it vastly, building a powerful narrative, and especially in bringing in new characters. Say what you will about our modern writers, but when they’re allowed to make new characters rather than write pre-existing ones, they tend to do either okay, or very good.