Personally, I'd just like to make a point that a lot of people seem to have overlooked when Bayohne said they'll eventually support custom UI mods.

-Custom UI Modding does not explicitly mean the same Mod API/Language/Feature Set as WoW, Warhammer, Aion, or whatever X/Y/Z Game you think of when they say 'UI Mods'-

A UI Mod API (Application Program Interface for non-technical people), can include additional features and access to non-standard information like WoW's does, or it can not. It could be a strictly visual UI modification set, such as only changing how your UI Icons look, or where they're placed.

Until you have more information, jumping the gun down SE or anyone else's throat and saying that 'UI mods will ruin the game!' or 'UI Mods will allow cheating!' or 'UI mods will create an unfair playing field!' or 'LS will start requiring UI mods!' remember: This game is -NOT- WoW/WAR/Whatever game you're thinking of. The term 'Custom UI' or 'UI Mod' is a -vastly- expansive term, ranging from minor aesthetic changes to complete overhauls or additional non-standard abilities.