I'm not sold on the Diversity approach, too much Diversity isn't good for a society. We only need to look to Africa, which is the most diverse continent on the planet, and it is plagued with war.
Look to Poland, which is arguably the most least-diverse country, and while it is fairly stable, it also lacks innovation and really hasn't do anything great.
It takes that precise balance. Too much, or too little and it just doesn't progress well.