"I think there is also a good case for type classes not being reified as modules or dictionaries or objects or what have you: they essentially exist exclusively at the type level. That is, the instances are a property of each type, not part of a module or anything like that. This also makes the syntax for types clearer: the => acts as implication and the type class acts as a predicate on the type."

Yes, redefinable instances of type classes feels a bit like monkey patching.

"Some other thoughts: I think laziness is a good thing because you trade performance for simplicity and expressiveness."

Lazy evaluation allows a more declarative way of programming.