What would drive them? Why are they in Starfleet? What beliefs do they hold dear?
Look at the reasons that young people today join the armed services. Serve their country, start their lives, education, adventure, leave home and community, work, three square meals a day.
Many are seeking to reinvent themselves, in basic training a new person is born.
What would be your ideas on a 'diverse' crew then?


In Penpals, a discussion between the senior officers revealed that they don't all agree on the Prime Directive. Take it further, a officer who conforms to the Prime Directive as part of her duties, but comes from a culture (on a Federation member planet) that opposes the very concept of the PD, and in discussions she openly advocates alternatives.


In The Enemy and Masterpiece Society, we saw two cultures that believe in killing children who aren't societal acceptable. Have a officer in Starfleet whose culture believes the same.


Increase the strangeness factor on officers who are Vulcans. They live 250 years and the average family has (hypothetically) 20 odd children, the reason they send them into the desert on the kas-wan test is because they want most of them to die.


Junk Star Trek's "modern secular liberalism" as a standard. Because our characters are a diverse group, only a few of our heroes will embrace this particular philosophy.Their beliefs on economics, religion, politics, government, capitalism, socialism are very different from each other.


Have a officer who fully lives Picard's no money - better ourselves philosophy, won't eat food or wear clothing that isn't obtained without money. And right next to him is another officer who enjoys having access to money, is seen spending it, maybe has investments and a business outside of his Starfleet duties, sees nothing wrong with it. Have the two (as a "C-story") get in the occasional arguments on their differing positions.


Something similar, two officers, one a person of faith, the other a atheist. Make them best friends, and while we're at it make them Humans. The two of them (jokingly) pushing their individual interpretation of the events in various episodes from their own perspectives. Kind of like the friendly banter between McCoy and Spock.


Diversity here too? Yes already.
... the kind of diverse personalities that would realistically never make it past the presumably thorough psych evaluations that Starfleet ...


But when does the screening process stop being about the best interests of the service, and become about loading Starfleet with people of a selected pre-existing mindset? Not everyone in the Federation is Human, why would Federation society (and Starfleet's selection process) be determined by Human viewpoints?

