If you're expecting a thesis then you're gonna be disappointed.
But 16 has been the average age of a groups Maknae since 2nd gen. Yes there's been exceptions but for the most part 16 was usually the youngest you'd get.
But now that Leeseo of IVE has started taking off I feel companies are gonna start going to 14 for their Maknae to try and recapture the same success. There may even start being two members in the group who debut at 14.
If this becomes the case then Busters were ahead of their time.
Korea is getting to a point where they keep wanting younger and younger and prettier and prettier. In their eyes Wonyoung is old news.
And that's scary for the future of kpop.