1. IDs are great.
2. Even if 4chan implements IDs, I don't really trust the 4chan team anymore. I'm not much of a computer person, but the fact that they didn't update the site for a decade just sounds so lazy. That, combined with pic related just gives me the impression that they're going to do the bare minimum and go right back to whatever not-actually-running-the-site activity they were preoccupied with. Like, the site you're supposed to be running just got shut down due to incompetence and neglect, and your response is, "tee hee, le epic caturday and ponies, amirite guys?" A year ago, when I started browsing /vt/, I had never really browsed a board that needed IDs, and I kind of thought there must have been some good reason for not having them. But this whole experience has really highlighted that: No. The mods were just lazy and retarded.
3. I'm not optimistic about the wider user base leaving the 4chan domain. 4chan's a popular site, and most users aren't affected by a lack of moderation, and even if they are affected, they probably don't know or have any reason to click on an alternate site that, from their point of view, functions the exact same way. (related to #3: the 4chan mods have no incentive to not be lazy and retarded) So when 4chan comes back, this may improve the quality here in the short term, as people with nothing to say return to their old habits. But, as with any place or organization where people congregate, there has to be a flow of new blood into the site to replace old users that leave. Otherwise, the place will get stagnant, boring, and eventually die off.