For what I learn from watching boxing, reading about his history and articles about it, the elite divisions throughout his history are the Heavyweight, Middleweight, Welterweight and the Lightweight. If we rate the boxers using this grades:
0- Bum
1- Bad
2- Mediocre
3- Good
4- Great
5- ATG or Legend
Which division of all the boxing divisions do you think has more 4 and 5 boxer throughout his history?.
They are boxers who are rated 5 overall, and had fought in several divisions, but you have to consider if that boxer were 4 or 5 above his natural division to consider him in another division too.

welterweight is and always has been the most stacked division. a lot of great middleweights were welterweights. It's probably due to the cross over inbetween featherweight/lightweight speed, and middleweight power.

well the classic categories of LW, WW, MW, LHW, HW re immediately at an advantage. the likes of LMW and SMW have not been around as long,

imo out all of the categories its gotta be the welterweights. middlweight has had some pretty good fighters, then HW, then LW then the LHW's.