Either way it doesn't promote employment longevity and job stability. It seems to be the same problem as inflation just in reverse.
I don't know if I did a good job explaining this clearly. Let me restate.
If decreasing prices (deflation) are caused by increasing productivity, then the average worker will deserve the increasing purchasing power his fixed salary provides, and he will never need an actual raise or a pay cut (as long as he remains exactly average).
But decreasing prices would also be caused by other factors in a bitcoin society, such as population growth (fewer coins per capita).