I think this is a recipe for disaster. First, there are basic things that you should do from the get-go, e.g. not using globals. Second, the problem with "eventually I'll do it right" is that by that time, your stuff is out in the open, used by clients and heavily depended upon, and you have no way of refactoring. A company that uses a bad piece of technology will suffer many years before they could replace it.
Depends on the language, I suppose. I'm more productive with Python when I write everything procedurally and refactor into functions, classes, etc. every dozen lines or so. It's more fun than writing UML diagrams (and seems to produce better code, too!).
Or do you think so long that your head aches and your colleague Hephaestus splits you open to find a fully-formed cooperative multiple inheritance hierarchy?
