Even the HDtracks can't hide the obvious production problems, there is still much compression on the tracks of each instrument, the cymbals sound weak and don't have bite and clarity, they sound dull and don't cut through the guitars. Also, as many of you said, James' vocals sometimes get drowned by all the effects that are applied.
It's a shame really, given the money that DT give for making those albums, and MM plays some great stuff which goes unnoticed behind the wall of sound of the guitars. If we had MP's level of quality on the drum production, i'm sure many more people would be amazed by the drumming. Just try listening to a song from let's say SDOIT or even BC&SL, and then DT12. Massive difference in the drum sound.
Also, James sounded great on his solo album, even with some effects at times, but on DT12 he sounds artificial on some tracks.