I would be against live pitch correction and overdubbed vocals on DVDs without coming out and saying some spots have been overdubbed for a valid reason. I don't mind post-production pitch correction. So I don't mind when DT use it. For instance, Score is one of JLB's finest live performances, and it's almost certainly been pitch corrected, not overdubbed like people claim, though I wouldn't swear on it - everything is possible. I think MP would come out and say that though, since he already shared what was overdubbed on Score (JP's guitar problem), Budokan (As I Am, some other stuff), Live Scenes (backing vocals), LATM (the whole dang thing)...
Another reason why I don't mind this is because all bands correct their DVDs to a point, we just don't know it because DT have a stronger bootleg culture than most other bands smaller than Iron Maiden and Metallica. One of my fave DVDs in recent years has been pitch corrected to death and most likely overdubbed in places and I don't blame them - a special performance costs a lot of money to produce and a lot of time to put together, and then a human vocalist can just have one bad day performing extraordinarily difficult music, and it all goes down into legend as "wow he really can't sing live".
From what I've heard on videos, father time has really caught up with James and he has some terrible performances, and he also has some good ones. But if they got Russell Allen or Ross Jennings to record their next DVD, there would still be autotune in there - our ears demand it and bands heed the demand.