Yup, I'm familiar with the cheater stuff, and I agree that the brain has subsystems which work better in some domains than others.

The thing about a well-designed modular architecture, though, is not just that it has task-optimized subsystems, but that those subsystems are isolated from one another and communicate through interfaces that support treating them more or less independently. That's what makes the kind of compartmentalization thomblake is talking about feasible.

If, instead, I have a bunch of subsystems that share each other's code and data structures, I may still be able to identify "modules" that perform certain functions, but if I try to analyze (let alone optimize or upgrade) those modules independently I will quickly get bogged down in interactions that require me to understand the whole system.