If there were multiple bitcoin style currencies that would be better. Sometimes the market demands more currency, and that is the natural setting of interest rates. In this type of environment, you can create "digital currency baskets" based on algorithms to have better strength and sell them as a financial product. That would allow for a more modern currency system that can fluctuate based on the market to meet population needs, innovation needs, and other issues that change the demand for currency.
Stable currency doesn't necessarily mean a fixed amount. It means an amount that is set by the marketplace. The best way to do that is just to legalize the use of any currency by anyone whenever they would like. We have the technology now to make all currencies introconvertible even at the retail counter.