Well said. I'm not the first to make the observation, but the principles of flat design also owe a great deal to the data-density work of Edward Tufte (
http://www.infovis-wiki.net/index.php/Data-Ink_Ratio) and the functionalist school of industrial design as exemplified by Dieter Rams'"10 Principles of Good Design"(
https://www.vitsoe.com/us/about/good-design). Where flat design diverges from these principles, I say go with originals.