I often argue with people that so-called 'flat' design leads to worse UX as it leads to a lack of clarity regarding actionable objects but also reduces the ability of the user to distinguish between UI components and various other page elements e.g.
download bmml source – Wireframes created with Balsamiq Mockups
Apologies for this slightly crude example, but the point is that it is much harder for people to quickly map out the various elements of a page if there is no depth and the 'but you could change the colour' argument just opens another whole can of worms around accessibility for colour blind users (many of which have problems navigating flatter designs). There's a whole host of articles online about problematic flat designs so I won't go into detail.
Could or should we be trying to move away from 'flat' design?
Is their any research or evidence to show a swing away from 'flat'? Are there any examples of how you can perfect 'flat' design and tick the UX boxes?