There is a bug with being under-valued. May not be working correctly with gems, but I'm not sure. Right now, with no belt equipped and at 216 hit rating, Rawr is telling me it's the 5th best plate belt. However, if I apply the relative stat values to both items (while no belt is equipped), I get at 293.8 DPS, while it's only showing up as 241.45 DPS. Doing the same to (which it currently recommends as BiS), I get 252.48 DPS, and it shows as 248.84. If I ignore both red gems in the , I get 240.04, which is a lot closer to what's being listed and is what leads me to believe it may have something to do with gems.
Comparing an item's dps in the charts to its relative stat values is a very bad idea, especially when you are as close to the hit cap as your are. First you should turn on enforce gem requirements, since most of the items above the belt were ones with prismatics when you already had your 3 used up. Then only 2 Ulduar belts are ahead of it, both of which are clearly better then that belt anyway.
I don't see anything wrong with the rings, Sif's Promise is the only one ahead of ruthlessness, and Surge Needle is top of the list. Yes, Rawr correctly applies racial expertise bonuses, which is why as a Dwarf Jawbone can be just as good/better then Betrayer.
Did you download the updated dll posted in this thread? It seems like you are experiencing the weird edge cases with haste, which is why I reverted the Rotation Simulator from using shorter spell gcds.