If you actually read something about the game, and the notes being released periodically they dont plan for content drops to be better than current tiers By content drops i mean quest items.
BT was cleared in Tier 3, while first tier raiding (Nax/Sarth/Maly) was cleared in T6... with there only being a 5 level difference in Cata either Blizzard won't upgrade items as much as in the past or make bosses so much harder.