I like this UI, it's clean, the options are to the point.

What's missing:

a) Extra ability bar for pet abilities
If I choose any ability bar layout (I use 3x2), the pet ability bar is static, locked, unmovable, stuck to the side together with bars 4,5,6, even though said bars accept modifications in terms of size, etc, from within the /vui menu. Please make the pet abilities bar act like a new bar that can be moved around.

b) Aura bars "limitation"
Right now, if I have 12 buffs (auras) and they're displayed, the option of "spacing" them does nothing, thus clipping all buffs duration text (text displaying "5sec" from buff A stacks with text displaying "xsec" from buff B) and so on.
There's also no way to resize the buff/aura window at all, because "Display per Row" is limited to minimum 8 icons, and not less. Lowering the amount would force the aura window to resize itself, making it fit in tighter spots, for people who want to make the UI as minimalist as possible.

c) Buff/Debuff UI elements movement
Please add mobility for the Buff/Debuff elements so they can be attached to the player Unit Frame. Right now, the buff/debuff bars can be active or not, with fixed positions, and that can result in clutter if still above the player unit frame. Having them offset underneath would provide less clutter overall.