I'm not a fan of Plasma's new default color scheme... It seems like a small and subtle thing, but the devil's in the details - that gray just looks so dull! Dare I say - Adwaitian! I like Breeze Classic much better, especially when used with dark Plasma theme (which is also much better than the default light one). Adds some contrast and clarity. Attempting to blend title bar with window content feels so 2010:)
Speaking about details - I wonder how much effort would it be to automatically hide that redundant hamburger menu for those who have already put one into their title bars... đŸ¤”