I don't think BMGs are in danger of getting nerfed.
PS3/NA Velaa 6000
Yeah, makes me wish I hadn't vendored all of the BMGs I've received since I started. I know I have had several Stingrays in the 4%-6% range. My current vendor bought Ray is pathetic at 21% but since I only need it for a relatively short time it's not really a big deal.
Just tested my personal BMGs at Zhena (slicer Protector and Shield Spanner) and the numbers are not nearly as consistent as the greens I picked up.
PS3/NA Velaa 6000
I was in a Co-op with the thread starter yesterday, guess what 2 weapons he used? Bmg and a Crimefighter.
I think I dented my desk hitting it with my head.
Please please please give us private coop in addition to private WM's.