It could be much better.

Remove the mechanic where mobs run back to their spawn points... make it if you run through the mobs never stop chasing you down. (Stop the stupid run through everything tactic)

Make the drops worthwhile.

Fix those 2 things, and the dungeon is not bad.

Make it really good add multiple paths which make you choose which one you do, similar to salvage in XI. (STOP BEING LINEAR)

The idea of more optional nms/bosses and such I also support.