I'm not a fan o this design - UX is worse and everything seems like screaming for attention. I like flat design because it's easier to guide user into the most important part of the screen and avoiding distractions. I could understand maybe 3d animation so you can embed somehow more information what this icon do but making this everything so colorful is distasteful for me. For desktop I still prefer to have just on hover have text to tell what icon do.
I disagree in part.
For the reason that in flat design, what is an interactive element and what is text or even decoration, is not clearly separated.
Especially people who are older and do not spend crazy amounts of time on their smartphones, since forever, struggle with flat design.
I could see this happening with my parents when the 3D UI buttons of the 80's and 90's and the skeomorphic design trend of the first decade gave way to flat design.
It's just not clear where a text ends and something that can be clicked or tapped on starts. When all you have to distinguish them is a change in background color or some flat frame.
You need to grow up with this tech or have an intricate understanding of digital interfaces to find this easy and/or natural.
I agree as far as using 3D objects goes. This is just a gimmick and a bad idea.
Any icon should be as simple as possible to convey meaning. Abstract; so it can be rendered in many adverse conditions without requiring change in shape or shading.
The icon sets in that blog post are the opposite of that.