I'm not sure why so many people, who play with controller, are stating that they don't have enough space to place abilities on their crossbars. There are, in my opinion, 128 easily accessible crossbar slots with an additional 8 available by holding L2 + R2 for a total of 136 crossbar slots to allocate abilities to. That's a significant amount of space! Even on the job in which I use the most crossbars, which is Nin, and I use 3 crossbars, I am able to easily access all of my most important skills on my primary and secondary crossbars with my tertiary crossbar having Kiss Of The Wasp, Kiss Of The Viper, and Shadewalker on that crossbar as those are my least used abilities as they typically do not have to be used multiple times per battle. R1+O to access my secondary crossbar and R1+Square to access my tertiary crossbar make for smooth crossbar swaps with R1+Triangle used to access my primary crossbar. Also, for any oGCD abilities that I need to keep an eye on, I place those on a hotbar located just to the right of my crossbar so I can see when those oGCD abilities are ready to be used.

I do understand that this is a bit off topic as the OP's primary concern is the amount of GUI management causing less enjoyment of the game itself due to having to pay more attention to the GUI than what is actually happening on screen and, as I stated in a previous post, I completely understand that it can become a bit much trying to keep an eye on everything, but I feel that when you have become proficient with the job that you're playing, and with good management of your HUD, it is possible to lessen the burden of having to keep an eye on the GUI and allows for more enjoyment of the fights themselves as you'll be more easily able to pay attention to what's happening on screen and enjoy the aesthetics of a fight, and character animations, while have to focus less on the GUI. This, however, is of course my opinion, and while it may not be as much of a problem for me personally, I do understand how GUI management can take away from other's enjoyment of the game.