Re: "the system has a more modern and 'flatter' look"
@Dave Bell : Look at how minimise/maximise/close has and hasn't changed.
hum ... dunno ... I removed to minimize buttons, as I use "present windows" instead, and replaced it with a "keep above" which allows me to have a window visible and on top even if typing in another one. Or take "roll-up" and "roll-down" when rolling the mouse in the title-bar, like MacOS-9 did in it's time.
Windows and MacOS don't propose these very useful UI features, only KDE (Kwin) does.