Give us content to use 18 Black Mages with Meteor..
Give Red Mage something worthwhile to do with that Enfeebling skill that hasn't been meaningful since 2006.

Finish the tower pvp system that was supposed to be in place in "Past" zones.
Idea? FFXI version of Dota sounds fun. Do it! FFXI has always lacked the actual "Fun" factor.

Fix Chocobo racing. C'mon even if you steal content from FFVII, we'd love it. We're the fanboys who still play this after 11 years, relax about wondering if we want the "new", let us experience the "Old" on an MMO scale.

Lots of good ideas, look around! Why introduce monstrousity when there is so much failed content that just needs some player feedback to improve? You're on the right track about reworking failed content, go for it! We're behind you all the way!