The "improvement" doesn't work very well as in practice, one gets the same appearance of [nearly] all title bars, only with the title text being faded out as the window is inactivated.
The range of colours to be assigned is very limited as well and there is no gradient fill (although the support variables are found in the Registry ...). Also not mentioned is that if you try to tweak the title bar settings following the advices floating around on web sites, every time you toggle the "Show color on Start, taskbar, action center, and title bar" option, ALL your modifications are lost.
However, the nasty "all white" title bars have gone. A relief. But wait, no, hey, still are there for programs doing their own colour management of the title bars. Ouch.
Some existing programs might be removed from your machine silently and without any prior warning. As most of these can be re-installed later, I fail to understand the rationale, must be an internal Redmont joke brought to bear on a wider audience.
For this "improvement" one has to download 3 GB. Really is the equivalent of a full-sized service pack, only that Microsoft now stopped calling this what it really is. They ought to admit that Win10 is a half-hearted, half-finished product.