I suggest creating an options to display all 3 layers of skill slots at once on the screen. Supporting as well the idea of putting macros in those slots and saving entire palettes just like XI.

The biggest issue with displaying only one line of skill slots at once comes when losing focus on it while being on the wrong/undesired row. You're stuck trying to get focus back on the skill bar, switch it back to your main offensive one, get back on the right target if necessary... precious time wasted that can get you killed and extremely frustrating. Iirc, using sub target actions and manual targeting while having an unlocked camera makes you lose such focus.

It would be nice to be able to resize this bar as well which will probably be necessary if we ever can display more than one row on screen.