Interesting. What I've found is that when I come up with some pattern that is hard to type, or I have two parts of a system that need to work together but the interface can't be typed simply or doesn't quite 'fit', it is almost always the case that changing things around until the types do work straightforwardly uncovers a better design.

This is definitely sometimes not easy, and of course it'll get more difficult generally the more code there is or the more complex (usually meaning bad!) the design is, but I'd almost put it the other way round to your perspective - the types are like the signposts in this design evolution and discovery process. They don't make it easier to do the work of refactoring a design, but they do make it much easier to understand when I'm going in a good/bad direction and also when I have succeeded.