Not if you are using Outbreak to apply diseases while also having 2/3 or 3/3 in Epidemic. Diseaseless blood is for lowbie blood tanks.
The only threat issues I have are with off targets when a frost DK is present, other then that I haven't been having threat issues either. I do not believe that it is an indicator of Blood threat being OP as much as it is of you getting your ability priority correct. Here is my
spec. I took some points out of things to get a few in Virulence so that Mind Freeze doesn't miss... while I obtain better hit gear... so until my gear improves, I don't have AM or BcB.... but its not been an issue in dungeons, as I am certain it will be in raids.