[jIyajbe]

My reading of the text is that "dimensions" he is talking about are the various ways of being good at physics, not the many ways an individual person can be talented. From the text:

"...What this suggests to me is that there are a huge number of ways of being a great physicist and that in turn suggests there are many ways of being a great physicist that we haven’t seen yet. Diversity is critical to the future of physics, I believe, because it is imperative to explore this vast space of physics talent and that means encouraging people who are different and who think and act differently..."