It could be neat to have content that is tuned toward single classes which is designed to be challenged solo. Sorta like the Maat fight in FFXI, except lass maddening as it isnt required to progress in the game's standard gameplay.

Tho, since this game is supposed to be a social game at its core, maybe make it 2 man content, and possibly focus it around classes instead of jobs.

Maybe something along the lines of WoW's challenge mode dungeons.

Iunno, I just feel like this game lacks more casual challenging content that can be taken on on a whim. One of the things I enjoyed doing in FFXI and WoW was taking on content that was trivial to a group, but more challenging solo, such as challenging NMs solo in FFXI or soloing heroics or lesser world pops (stuff like the warbringers in MoP, but sadly, soloing those has been trivialized by further increases to ilevel).

Also, didnt really know where to put this... doesnt really fit dungeons, but it seemed like the right place.