You misunderstand what I was saying. I never said Challenge Modes were part of progression. The old version of "heroic" dungeons was removed from the progression path. The MoP heroic dungeons are intended to be equivalent to the previous exp max level normal mode dungeons. Comparing heroic previous exp dungeons to heroic MoP dungeons is not an accurate comparison because they fall in different levels of the progression path.
TBC/WotLK/Cata Progression : hit max level -> do normal mode max level dungeons -> do heroic dungeons -> raid
MoP Progression : hit max level -> do heroic dungeons -> raid
So the step right after "hit max level" is where you should be doing the comparisons. That was explained by Blizz before MoP launched.