[z3phyr]

Abrash wrote in his graphics programming black book, and I quote, Carmack's law ->

"I’ll take this opportunity to coin Carmack’s Law, as follows: Fight code entropy. If you have a new fundamental assumption, throw away your old code and rewrite it from scratch. Incremental patching and modifying seems easier at first, and is the normal course of things in software development, but ends up being much harder and producing bulkier, markedly inferior code in the long run, as we’ll see when we discuss the net code for QuakeWorld. It may seem safer to modify working code, but the nastiest bugs arise from unexpected side effects and incorrect assumptions, which almost always arise in patched-over code, not in code designed from the ground up. Do the hard work up front to make your code simple, elegant, great—and just plain right—and it’ll pay off many times over in the long run."

[ksk]

If you watch any of Carmack's recent keynotes you'll see hes advocating doing the opposite now. Whats changed is the multi million dollar risk profile associated with modern game releases, the huge increases in the sizes of the teams, the large scale complexity of modern AAA code-bases, etc. And also the fact that most games now are data-dominant rather than being sold entirely on some new game-engine feature(s).