The only problem I have with flyW and WMMA, for that matter, is the lack of finishing ability. I don't need blood or injuries, I just like someone to win without the judges having any say in the matter.
Also, with FlyW (not WMMA) the scrambles are almost too fast and frequent for me to follow without watching twice. I love me a good scramble, trust me, that's where you see some of the best fight IQ/flow without thinking but I have a hard time following those blazing fast little guys.
Compound the two issues and that's my entire problem with them. I am always impressed with lighter class technique. It's indisputably better but it's all too fast and it nearly always goes to the judges.
So basically, I know that it's me, not them. They're great.