Here's my example of your HUD.
You don't need a billion letters and buttons floating around to designate what does what. There are in-game tutorials for explaining that
Also, I didn't find the EXP bar really that helpful. It just added another cluttery object to fit in and another different color to mix with.
The overdrive bar here is one color, but that's not to say it can't change colors as it moves, but my intension was that the bar grows inwards from the sides and the vertical lines designate a new zone in the overdrive bar.
Having to know what characters have potions I find is extremely cluttery. I think it's useful to know what character is next in the line up to switch characters, but knowing what kind and how many potions they have is not.
I wasn't sure if this was your intent, but I thought it would be neat to display the weapon and shield the current party leader has equipped. It also designates the 'attack' and 'block' functions. Again, all you need a quick in-game tutorial that tells the player that
this button does this and
that button does that and they're good. Plus they can just reread it if they forget, but in most games it's extremely self explanatory.
Here's a higher resolution image (.png) of the HUD.
Here's a kind of what it would look like when switching players:
Notice that each sprite (in the left corner) becomes more and more opaque as they near becoming party leader. Party leader is 100% opaque, next is 60%, then 40% and then 20%.
Also, my last note, is that your button layout is really awkward. It doesn't feel natural to have my hands like that on a keyboard.
This is only how I think the layout should be:
Action Buttons:
Q, W, E, R, T
Attack:
X (or Z)
Defend:
z (or X)
Potions (in any order):
A, S, D (if there's a 3rd)
Overdrive:
SPACE
Menu:
SHIFT or ESC
Select/Accept:
ENTER
Deny/Cancel:
'
I think Tab is still a good choice to change party leader.
Also:
This HUD took me forever to do today .____.