Useless metric like QBR when a third party subjectively grades.
Like others have said about the All 22, don't know what plays were called or who ran the wrong route etc. therefor it's an inaccurate metric, same for DVOA.
Does DVOA take into account what plays were called on both O and what defense was called? Does it take into account who is playing injured? Who missed the hole, ran the wrong route, or missed a block, or covered the wrong guy? No! Then it's a useless stat!
That said, yeah the defense wasn't very good this year but stats alone says they were average. It is what it is.