When there's a level cap expansion, tuning the new content for endgame-geared players is a totally bonehead move.

Say some months after the 2.3 patch, Square bumps the level cap to 55 (which would be smart, a big bump would be silly) with the first expansion pack. The smart thing to do would be to balance the leveling content from 50 to 55 for item level 55-65. The level cap dungeons (4-player) should be tuned for 65-70, dropping item level 85 (just how WP dropped i55) and i90 (just how AK dropped i60). The first batch of Full Party content ought to be tuned for i90 average, which means that those of us who are bleeding-edge through the entire level 50 endgame should have a slight advantage in the first round of raids, with the bulk of the playerbase catching up quickly.