If you're a designer, you haven't had a chance to stop reading about flat UI design in months. Its everywhere, hackernews, twitter, dribbble, your grandpa's hand-me-downs, the list goes on.
Like most design trends (chunky buttons, web 2.0 badges, grunge, noise, whatever else..) flat UI is likely just that. A trend people will inevitably become sick of after it has saturated the market.
Flat UI follows Dieter Ram's 10 principals in the majority of ways. But I think it fails on two:
- Good design makes a product understandable
- and Good design is long lasting
So if our main goal is to make everything intuitive (to keep a user from having to think) - its easy to reason that we should be using forms of visual communication with which people are familiar.
I.e. You're familiar with logos always being in the top left. Or that in real life, a door knob indicates rotation + pulling/pushing to open/close, whereas a metal strip generally means push.
My main concerns with flat UI - are that while it is gorgeous, its not familiar. We live in a world of multiple dimensions - and we get visual cues from those dimensions. Even a newspaper or magazine may have a flat UI for content - but have 3D UI for navigating between pages.
I think that flat UI in it's current growth is mostly being mis-used, and overused. Designers must give more consideration to function over style.
Just because something looks good, doesn't mean its easy to use, or useable at all.
I think the real answer - is to treat it as one more tool in your belt and use it when its appropriate - not because it's the "hot" thing to do right now.
Most problems I see include a total loss of visual hierarchy, indistinguishable depth and layers (i.e. hovering menus). Things don't work like that in the real world - and the way you design should take cues (not mimic) from real life as best as possible.