I like the new theme in the Beta I think its moving in the right direction.
I find the fields and buttons a little too big - see screenshots attached.
I would love to see collapsible dashlets (you can close them and move them but they won’t collapse
I agree with DomJ I think that the height of fields and of spacing is too big. I would reduce it slightly to make it more compact.
Personally I wouldn’t use dark violet in the top bar (but this is only a personal taste).
For the rest it looks great to me from what I have seen so far.
There was a similar discussion on Github
https://github.com/salesagility/SuiteCRM/issues/1665
but it seems it is too early to discuss the new theme - I think it was published merely as an “appetizer”, a sneak-preview.
I see on Github that the theme is still being heavily worked on, so I expect (hope) the next version we see will be quite different and most of these obvious flaws will be addressed.