The best UX test for me was that my kid at age 4 could easily manage iOS apps or sites with bootstrap-like design, but would get totally lost on pages with the

The best UX test for me was that my kid at age 4 could easily manage iOS apps or sites with bootstrap-like design, but would get totally lost on pages with the material design. In their effort to make it super minimal they've removed too much of the visual hierarchy. If you can't read, you just don't know if something is a static label or a button to click. And that means that even if you can read it requires some extra mental strain to navigate it quickly. Obviously, like with anything, you learn to use it with time, but problem with that is that even a small change will confuse you again. Put an element in an unexpected position or too close to some body of text, and people will miss it completely.