Let me give my feeling about your work broken.
First: I appreciate your efforts in trying to "humanize" and "efficientize" Blender's interface (though it might be needless to say: that will make some people very nostalgic of the 1.8 UI : some evolve and others, well, [looking for a polite way of saying this...] don't evolve (hrms...))
You seem to be on a good track, though there and quite some things that still need some work (the UI is huge, so there always is some work).
Here a some crits, that i hope are constructive :
Although I first though that floating panels were a good idea, now i doubt: they look like a constraint to the coder (where shall I place this thing? there's already so much in this panel, should i create a sequel to this panel ie: edit tools 2) and to the user (where do I find...)
Ton was right when saying that people like the "dashboard" principle: everything is visible or at least easy to find. I might want to change that to :"everything is visible or at least easy to find in one given context"
So the floating panels as they are now in Blender might not be the best solution. However, your work is still in its very early stages so I will wait to see how it turns out.
Anyway, what i suggest is to use a bit more the buttongroup functions that are available in the rounded theme. The render button (F10) look very cramed up with the new theme and arrangement compared to the previous version. (shouldn't "Field" "Upper" and "Freeze" be grouped?)
Also, you might want to at least evaluate Labelled buttons versus Icon buttons. I see a few advantages in well done Icons : as I'm very concerned by the l18n of Blender, this would make things a lot easier. Ton suggested to only translate tooltips and not button labels. To lots of users and to me, it doesn't make much sense: "Blender's localised!" "You sure? all i see is english...". Buttons must be explicit, and keeping the original language is not the way to this...
Icons would 1) justify the non-translation of the buttons
2) give instant feedback, if they are well done.
3) Save Space.
4) Make translators happy...
Another thing that would help translators is bringing button labels OUT of the button, at least where possible: toggle buttons have no need to have the label inside of them! next to them is good enough!
Some other things that could be done to go in the DashBoard way is a thin line with a summary of the context's activated features along the (3D view?) header (with the selected object). (in a coded way... dots, colours, something... hum, is this really a good idea?).
Oh, and will you tackle the headers?
They have a few problems : they do not support vertical position, and the hide the information. I still thing that, for example in the Buttons Window's Header, all the conexts should be visible at once, grouped, but all visible and accessible. Having to click on the material button to acces the world button is quite annoying, and sometimes F8 is just too far (this means, that the "USE THE HOTKEY" argument is not valid... we're trying to make the UI easier no?)
Having said all of this, well, I shall leave you to your thoughts.
Oh, I forgot, the arrows in the numbuts aren't always very well placed and are EXTREMELY annoying for lisibility and translation. What I've already done is recoded that function to draw the arrows, so that size, shape and position aren't hard coded but given by the calling function (ie: each theme can have a different arrow size etc, have them stretched vertically to make isocel triangles). However, the only thing to do to call back default is to send some zeros as arguments.
Why did i do this? to get a hand on C, and to place those arrows out of the way! You might not need to do all this, just move them a bit towards the edge (I use 2pixels and it looks good enough)
Well, this has become a long post, now I'll let you work