I like my people to do more than prototype for this kind of work. It's probably a semantics argument, but we prototype as part of design and intend for it to be trashed/rewritten, whereas what I was speaking to above is real development work that will be used, definitely not polished but 'works' enough to keep moving forward.

That often means "getting the bones" right, but occasionally cutting corners to get stuff done. If your focus is having a good product, which frankly it most of the time should be, then done is better than perfect.