Bitcoin is not untraceable money, it can be even more traceable than normal currency. It could be stablished as a law that public money when being spent in the blockchain needs to be auditable by the people (identities of sender and recipient known), and this way you would end up with even less corruption than the current system.
> Deflation means that the rich will get richer
Wrong. Rich people don't have money, they have holdings. Most of the holdings that rich people nowadays have are not money. Deflation just benefits the savers, as opposed to the spenders. Some savers might be rich but not all. Incentivising saving instead of consumption may make the planet a bit greener. Plus, if one day we stop measuring cryptocurrency value with a fiat-unit of measure, maybe we find out that the cryptocurrency value is actually the stable value. The asset that is not stable is the fiat currency because it's being depreciated all the time. The day all stores in the planet denominate prices in cryptocurrency, the bad consequences of deflation (hoarding for the sake of profit) will be almost imperceptible.