The problem is that every new viewport lands on the end of the list from where it can’t be moved.
On the second screenshot, it is already visible that the order of the viewports in the bottom bar is not representing the same logic of my viewport layout. If I would need to make another viewport it will just be placed on the end of the list and make even more mess.
I could just rearrange viewport layout, every time I add another viewport, just to keep the same order as on the bottom list, but of course, this is an insanely unproductive way to do it.
To add a little more, I would gladly see an option to further split the bottom list into user-defined groups, so one can see out more of the corner of your eye.