Two sections that I would like to see would be writing secure code and somewhat in line with Andy Lester's suggestion of knowing what the problem is, or in other words, ensuring that you have the correct requirements.
In regards to writing secure code, it's not that unusual these days to hear about various errors in code that lead to security issues and having the common problems summarized in Code Complete could go a long way towards helping developers avoid some of the problems. Likewise, now that we are starting to move in more of a web-centric environment, it might be appropriate to mention some of the common security issues around web development in such a section.
Next, the issue of knowing that you are solving the correct problem and ensuring that you have the correct requirements. This is actually something that has popped up for me quite a bit in my own job and while others may help gather the requirements, it is still on the developer to implement those requirements and produce the final product that will be delivered. As such, having some information in Code Complete to demonstrate to the developer good requirements and also when you should take a pause to ensure that you are solving the right problem. As part of such a section it might also be a good idea to mention "non-programming solutions" as there are also situations where the program might be hiding a "process smell" that should be resolved outside of the program itself. This might be a little bit off topic for Code Complete though, but worth mentioning.
All this said though, I do agree with the others in regards to making the book a bit less wordy. Likewise, over time I have found myself referring more to the project management and system design considerations as opposed to the source code discussions which leads me to agree with others that its a good book for junior to mid-level developers but over time it starts to offer less. Thus, it might just be a good idea to focus a bit more on what distinguishes a senior level developer for a junior and also add some additional information that would be of interest to a senior developer.