Adding another one: the advice on "Feedback methods" (don't send out engagement surveys, just walk around and ask people how they're doing) is incredibly hard to get right.

It takes a remarkable amount of trust for a random individual employee to feel confident that they can voice their concerns to management. And that trust takes an enormous amount of effort. If you're a manager and you're not absolutely sure that your employees would feel free to speak their minds, giving them a risk-free way of doing so isn't a bad idea. Employees feeling they can't speak honestly to someone who is in control of their livelihood isn't a "problem with communication", it's the status quo at the majority of companies.