An Introduction to Game and Mod Design is a piece written by Blbpaws, the Mod Manager at C&C Labs, and the Lead Designer of the All Stars mod. In it, he aims to give a perspective into the basic design process of a mod, what goes into a design document, and how to create a balanced and interesting mod or game. For the last section, he uses C&C All Stars and Command and Conquer 3 as case studies to illustrate various points. Even if you're not a game or mod designer, you still might find this article interesting because of how it explains the design process and important concepts, and because of how it offers a window into C&C All Stars and C&C 3 in terms of how product goals affect the design of the final product.
An Introduction to Game and Mod Design by Blbpaws
Part One: An Introduction to the Elements of Game Design
Part Two: An Introduction to Balance
Part Three: Creating Variety: All Stars as a Case Study
Part Four: How Goals Affect Balance: C&C 3 as a Case Study
Part Five: The Art of Playtesting