Yeah I think true mocks often lead to fragile, hard-to-read tests. A text which expects a bunch of specific interactions with a mock is white-box, whereas a test which tests the state of a fake after the operation is complete is mostly black-box. Then, if your dependency gets updated, only the fake breaks, rather than all of your test expectations.

A particularly complex fake can even be unit-tested, if need be. Of course, if you're writing huge fakes, there's probably something wrong with your architecture, but I feel like good testing practices should give you options even when you're working with poorly architected code.