It seems like taking this pattern to an extreme would make it hard to track all the business logic that's going on as each class gains it's own quirks and rules.

I agree. I think that we have to use some sense where applicable. However, the overall concept, I feel, is in the right direction for maintainable code. I would much prefer this over the other extreme where classes and methods are huge. I've seen some classes with over 1000 lines of code and also some methods with 600 lines of code. They're completely unmaintainable and writing tests for huge methods is near impossible.