I see a program as a theory, a theory of the problem it solves. You can see how well it generalises, if it is needlessly complicated (Occam)... and in some magical moments, you'll find it predicting phenomena you hadn't explicitly anticipated.

So I think a program's conceptualisation of a problem is the most important thing - more important than data structures or code. Though, data structures are usually closer to it, by representing the concepts you model.

However, it's really hard to get these things right. Linus created both his great successes (linux and git) after experience with similar systems (unix/minix and bitkeeper). Being able to play with an implementation, experience its strengths and weaknesses, gives you a concrete base to use, reason with, push against, and come up with new insights - it's enormously helpful in seeing the problem.

But that's a grand vision - I wonder if Linus is also talking about programming in the small, each step of the way, as a low-level pragmatic guide. I don't like git's interface or docs much, but the concepts are great, it is implemented really well, very few bugs, and even on ancient hardware boy is it fast.