Diversity adds richness - diversity in thought, diversity in age, diversity in maturity, diversity in skin color, diversity in expertise, diversity in gifts, diversity in political leanings, diversity in religious inclinations.
Diversity, however, does not necessarily imply strength.
Strength comes from unity, unified effort around a noble and worthy vision.
The best leaders (and the ones, unfortunately, that are hardest to find) are the ones that encourage us to celebrate our diversity and teach us how to respect our differences, yet have the ability to help us see the better future we can create through coalescing around that vision.
That kind of leader is worth more than his/her weight in gold.