The UFC isn't ready to expand the division as deep as the others. It is still extremely new to the UFC.
Bottom line is they have all the top 5 flyweights in the world. 115s aren't going to come in and do anything when 135ers are dropping. Japan fighters really aren't good anymore, they rack up wins over on that circuit, get built up...then flop in the UFC. I can't think of 1 Japanese circuit fighter who has translated well to the UFC recently.
Like I said, sure they can go out and accumulate MORE fighters, but they have the best right now. They have went out and signed the divisions #1 fly a few times already. But they already had the best flys in teh world...they were just in the 135 division.
It will grow slowly just like 135 and 145. It isn't plausible that they just go out and sign the best 20 flys in the world all at once. Many of those guys don't want to come to the UFC. Many Japanese fighters want to stay on that circuit and be an elite fighter there than an average UFC talent. When fighters separate themselves from other the UFC will snatch them up when they can.
Awww man I just hate it when people group people together like that. I bet Crusher would come in and be a top 3 FW in the UFC right away. IMO Soo Chul Kim at 20 years old is maybe the best BW prospect in the World right now. He would wreck a good % of the UFC roster right now. That kid just keeps getting better and better and is unusually strong compared to most Asian fighters. Saying those 115lbs couldn't use speed, technique and pace to do something similar to what Mouse did at BW is crazy as well. The top level 115lbs guys are great fighters and often times fight 125ers. These guys are better then most guys sporting those magic 3 letters on their gloves.