I think the look depends a lot on the icon set in use, which can be changed in the settings. Personally I use the Elementary SVG version on my Plasma Desktops, I find those icons to be clearer and neater than the ones in the Breeze pack. Also the default Font Liberation Sans, while a fine font, has a certain look that looks slightly dated somehow. If you change the default style for all documents to some other font, it looks a lot fresher :-)