At this point, the only thing stopping the Elfcation, is the playerbase.
It's...understandable? I mean, we are in a position right now where we can do a
lot of lasting good in ways no one has been able to do for millenia, and going on the elfcation means a lengthy arc across the sea hunting druchii raiding parties where our help is appreciated but not needed (else Ulthuan would be organizing more forces for the effort).
Would it give us useful traits upon completion? Yes, and that's definitely a strong argument for it. But we could just as easily hold off on the elfcation until, say, Eike becomes a Journeywoman or we make a new set of enchanted robes for defense or the our involvement in the Waystone Project comes to a close. The opportunity is literally "between now and when the world ends", after all.
It's easy to see why people might be put off about putting the current arcs on hold for a year IRL (or more, perhaps) to go to a place where all of our friends and acquaintances are out of contact and we can't even bring our apprentice.
Last time we had a choice for an arc like that, we knew we'd probably be going with a number of characters we knew and liked, we knew we were on an important and time-sensitive mission, and that our assistance could be decisive in the entire effort's fate. And it very much was, between rescuing Karak Vlag, using Rite of Way to shorten the journey significantly, acquiring a lot of food to keep the expedition fed, negotiating safe passage thrice over, getting the expedition a lot of reinforcements, magical firepower, and airpower, and securing a cleared High Pass for the journey.
Personally, what would be needed to make the elfcation really feel worth it is getting a spell creation trait out of it, and spending months working alongside the warriors of Nagarythe might just do the trick.