I too read de Bono's Thinking Hats book and found it worth considering. It reminds me of Nietzsche's Perspectivism [1]

I don't think having a fixed set of N perspectives is the correct approach. Rather, it is often a good idea to understand that there are many perspectives to view things from and to encourage productive perspectives when possible.

One frustrating thing I find with people I consider closed minded is an insistence on viewing every single issue from a single unchanging perspective.

1. https://en.wikipedia.org/wiki/Perspectivism