Ok let me run down why some of the rankings are what they are.
First off, Rich has decided to move up to LHW, that is why Sherdog has him ranked there.
As for WW. The rankings are not about what a fighter has done over his whole career, it abotu how good the fighters are right now. Like BJ pointed out, MAtt has not fought in almost a year (in most ranking systems inactivity drops a fighter down the rankings) and he is 1-3 in his last 4 fights. Once Matt beats Serra Im sure he will jump back up to 5 or 6. Shields has won 11 in a row and in that time has beat Condit, Okami and Charuto. As much as I dont like the guy he should be ranked i nthe top 5 untill he gets beat. I think that Karo should be off the list and everyone under him should be moved up one spot.
As for LW, why the hell should Aoki not be #2? The onlny person I could see being ranked above him is Hansen, but Hansen lost to Alvarez and Aoki crushed Alvarez. Aoki is clearly the 2nd best LW in the world and you can make a strong case for him being #1. Now I know somone is going to point out his loss to Mach, but that was at WW, you cant drop Aoki in the LW rankings because he lost a fight at WW. As for why there are som many non-UFC fighters in the top 5. Well thats becasue DREAM might have the best LW fighters in the world right now.