Good little article, but it's a shame you focused primarily on dribble designs and weren't able to go back further in time to the early 2000's...
Ok. Button is inexistent before 2009 - The Dribbble Timeline
This is a really thoughtful article, thanks for writing and sharing it! :)
While this history is open to interpretation, my broad take-away is that not all trends are objectively better because they are newer. These all have trade-offs that exist completely independently from the year(s) in which they were trending. While the intent behind many of these shifts is often well intended (by the professionals who adopt it), I suspect it has more to do with our obsession of wanting something new and different than it does about wanting to improve the experience for users.
Personally, I think 2012 and 2014 are both great examples from two directions/philosophies. These two are probably the the most effective solutions for real users across most groups. 2014 is more likely to have contrast issues depending on the background which puts it at a clear disadvantage to me.
Amazon dash; skeuomorphism gone mad!