Worst competition in FX? U.S. EU and the rest of them?

Hello, I have a question to see long term perspectives for the currency in general. Who gets more in its value? And must USD be the strongest currency in the world?

The price movement seems mere competition of devaluation for me (who gets worst and the “less” worse get incline in value).

For example, Yen and Swiss are stable currencies and are increasing in their value because other currencies particularly Euro and USD are doing terribly such as worse-than-expected economical release"s" from the U.S. and negative bias of Euro in its long term (although some Greek news helps to rise its value temporarily).

So, whichever “stays same” get better relatively, and which ever gets worse get devaluation; is these correct for viewing the current situation? If so, is USD, as the leader of the world, required or forced to be better than other currencies; or even now, USD is untrustworthy, so many people go for Gold, Yen, Swiss? Are Yen and Swiss able to be the leading currency in soon future?

Thanks!!