The Japanese Yen would rise to be the dominant currency, with Japan eventually becoming the top economy. Then it was the Euro that would inevitably conquer the dollar in importance. Then it was the Yuan that would of course conquer the dollar, with China becoming the dominant global economy - that prediction is also going to fall flat.
The dollar primacy is stronger today than it has been in 10 to 15 years and it's gathering strength - pulling trillions in capital away from the rest of the world, and crushing emerging markets in the process - even before the Fed has raised interest rates. So long as the US avoids going on any more massive spending binges that blow out the budget (2000-2010), and avoids starting any new trillion dollar wars, the dollar will continue to gain in dominance rather than lose it over the coming decade.