FFXIV's UI needs help, and it needs help fast. Faster than SE's development team can provide, in fact. That's why SE should implement support for player-created interface Addons as soon as possible. If SE did this, and got players involved in the creation of better UI elements, players would quickly create solutions and solve all of the UI problems within two or three weeks, a rate which any development team simply cannot match. This is certainly no fault of SE's, as all game development teams have limited time, limited resources, limited man power, and limited money. However, none of these limitations apply to the playerbase. If you let us get involved in making the UI better, SE, through the use of interface Addons we will cancel out and nullify one of the biggest complaints about FFXIV (i.e. the UI).
With player-created interface Addons, all of the UI problems could be completely solved by the end of the year, and SE wouldn't even need to do that much work. Just give players the support they need to create, import, and use interface Addons, and we'll do all the work ourselves, and FFXIV's UI problems will be solved before you can blink.
And considering how much harm has already been done to FFXIV's reputation, I think it's pretty obvious that time is of the essence. SE can't wait around while the development team takes their time to fix all the problems with the UI. The problems need to be fixed now, and only the playerbase has the time and resources necessary to accomplish that.