I gave up on my zeta after I got my Zenith...
But, one thing I can see to make the dungeon runs more interesting would be to perhaps introduce a consolation prize of sorts.. Put in some crafting mats that are worth some money so people farm it.. I know some already have it, but most of the existing ones are crap.. I'm talking like Inferno Horn kinda deal, hundreds of thousands to maybe a million gil in price, of course with a low enough drop rate so it is sought after. I would like to see some of those.