User blog comment:Moab of the rising dead/what would you like to see more or less on terraria/@comment-24102751-20131028083738

I think the underworld should be expanded on (i.e. be made slightly larger depth-wise, another underworld-exclusive boss, a new ore (maybe), several more useful crafting materials, new hardmode underworld enemies).

I just think there should be more reasons to re-visit the underworld, it seems a player really only need to visit the underworld once or twice, then it becomes uninteresting.