Emerging market investors have faced testing times in 2014. Bonds, currencies and stocks have been volatile. The Russian ruble crisis is just the latest shock, and may yet dominate the start of 2015. But deeper challenges still loom.

First, growth isn't what it used to be: Between 2005 and 2009, emerging market growth outstripped that in the developed world by 5.5 percentage points on average, according to International Monetary Fund data. Over the next five years, that gap is forecast to be just 2.8 points.