Why fetish? Would you rather hold Mexican peso, Turkish lira or something else? People obsess about US dollar as a reserve currency because they know that they, or someone else, could go into US and spend the money to buy real stuff. They also expect low and manageable rate of inflation, as it was observed for more than one hundred years in the US.
The US economy may be prone to inflation, but the inflation has been mild since the 80s. I am also curious about the "deficit" you're mentioning. Being a market economy, there can't be a deficit in the US. If there is an excess demand for any good at a given price, the price will rise until the quality demanded equals the quantity supplied. The deficit happens when the price of a good is set artificially below its market price, like it happens in communist economy or in places where a totalitarian government attempts to fix a price.
So why else people prefer the dollar? The exchange rate does not fluctuate as wildly as that of other, lesser economies. A run out of the mill hedge fund can probably collapse the exchange rage of Ukraine hrivna or Turkish lira, if they feel like it, but attacking a US dollar on exchange markets is something no one can afford.
What else is there? It's a huge economy, one of the biggest in the world, and just like most of the first world economies, the US government has no problems collecting the income and sales tax. This means that the debt of the US government is always guaranteed by the affluence of the economy and the taxes collected.