Quote Originally Posted by Wolfie View Post
WOW's default UI has steadily evolved over the years and "kept up" with addons, precisely for the reason that the developers didn't want let addons feel required. For all it's problems, UI development is the one thing that you cannot fault WOW on, because it's been getting it right since day one.
The purpose of user interface addons is to allow users to find ways of improving the UI rather than leave it up solely to the development team. Rather the development team simply would spot useful interface improvements and include them in future updates.

No one else allows this type of customization of the UI. And for one very good reason. It's a very stupid idea. What you get is a small few addons that do noticeably improve the game in some way or another. The vast majority are trivial improvements, copies and variations of other addons, or just plain bad user interface additions. Blizzard has never offered documentation, let alone any type of guidance to what makes a good interface addon.

The problem with UI customization with FFXIV is that the development team would have to spend a large amount of time developing the infrastructure to allow users to extend or replace the current UI. While presently the game does use lua for client side UI, it's not designed to be extended.