There has been a hope for a return to fundamentals in the foreign exchange markets with a decline in foreign currency reserve buying. In the last 12 years the foreign currency reserves held by central banks has increased by a factor of 6x from $2 trillion to $12 trillion as measured by the IMF's COFER data, but that flow has been changing with declines in reserves as central banks have sold reserves to arrest currency declines.
The return to fundamentals has come back with a vengeance for many countries. Falling commodity prices, capital outflows, declining economic growth have all led to declining currencies not as a means of enhancing exports but as a reflection of poor economics. The result may be a change in the terms of trade and exports but not because of anything central banks have done.