I think what has happened is that most, if not all, content were planned (not designed) back even before 2.0 was released. I'm talking about an outline plan here & how they fit into the narrative. When 3.0 was being made these dungeons were under construction & things like ilevels were set. However, they didn't have the benefit of knowing just how the player base would take to the new actions etc that came with 3.0.

The result is that dungeons & other content that really would have been ideally released as part of 3.0 are being released "too late" in the cycle. Look at the gear we're getting from the Expert Dungeons - it's i225 which should have been part of 3.25 or earlier & as a result 'difficult' to complete. The tuning of gear levels seems, to be, to be all out if kilter since 3.0 dropped. Just look at 3.4 where the leap is effectively 30 ilevels whereas 3.2 to 3.3 was 10 (if you disregard Savage content).

4.0 needs to sort this out as it's the next chance to get it right.