I had 4 bar stack originally, i went to two bars for a better organized ui and to bring the size up a bit (bad eyes). I had crammed everything on the original demonic ui, it was just to cluttered for my eyes.

Now its split up. Mounts, consumables, and professions in one area. Potions, trinkets, and health stones in another. All of my spells centered. Many people use tons of key binds for playing and can pile things together without having to actually look at their ui. I am a clicker for the most part, the only key binds i use are for my bottom row of spells and my health potion/stone. the rest i click. Even with it squished i have plenty of room around my action bars, just trying to avoid clutter.