Differing utilities for loss vs. gain introduce an apparently absurd degree of path dependence, in which, say, gaining $10 is perceived differently from gaining $20 and immediately thereafter losing $10.

Yes -- the example I've seen is that a loss-averse agent may evaluate a sequence of say ten coinflips with -$15/+$20 payoffs positively at the same time as evaluating each individual such coinflip negatively.