Functionality is important, sure.
A consistent, accessible, good looking UI as well.
This is really not the case now.
And a UI should not let me make think.
About the panels
Most of them have their individual button sizes and logic.
See 1, 2, 5, 6, 7.
In 5 the caption is clipped.
3 has another background color than the other panels.
Scrolling by mouse wheel:
Doesn’t work as expected in 2, it does not scroll to the end without using the scrollbar.
In 3 every single scrolling cause a refresh, and it feels like pixel-wise scrolling.
3 has a good icon size.
4 has micro icons.
This is mixed.
2, 3 have a good readability.
4 has a too small text, just as small as the captions in other panels.
No doubleclick functionality when clicking between 2 columns in the header, should set column width.
There are more issues, the above is not a complete list.
I know the panels are made by different persons and they do not use the same tools.
This might be the cause for the different look and behavior.
But not a valid reason.