Seeing how one of the reasons why SE don't wanna open up universal glamour system where, as an example, a WHM can use plate like WAR can, is that they want to keep the personalities between each job category and not make things confusing visually, I doubt we'll ever see a system where one can switch the visuals on the skills.
It's a nice idea and it reminds me of back in City of Heroes/Villains where a player could costumize the looks on skills with visuals and colors.