What is the comment about the dot product's "complexity" supposed to mean? It seems to me like the perfect example of a MAD operation.
In general this page seems extraordinarily sparse. I would propose tips like deferring normalization when all the factors are nearly normalized, and identifying partial sums and products that are shared so they aren't redundantly calculated. Also, the dot product of the surface normal and the near plane can be passed to the fragment shader so that fast approximations can be enabled for nearly-perpendicular polygons (analogous to Level of Detail.) I haven't added these to the page itself because I'm not an expert and I'd like a second opinion.
At the very least, the page should include profiling tools and books/articles about optimization. After all, this is under "The Industry's Foundation for High Performance Graphics".