Productionize usually means "rewrite". I think that software engineers in general have become too averse to rewriting code; as long as you do it with the same team that wrote the prototype, it's often a good idea to throw away everything and start from scratch.

The development cycle for me is much more about collecting requirements than coming up with a design that satisfies those requirements. That's what iterative design is about - you try something out, see if it works for the user, see what other features are really necessary for it to work for the user, and then adjust as necessary. Once you know exactly what the software should do, coming up with a design that does it is fairly easy.

My current project is nearing its 3rd complete rewrite since September, plus nearly daily changes that rip out large bits of functionality and re-do them some other way.