One of the reasons that Mr. Trump beat Mrs. Clinton is the reaction to political correctness. Questioning the diversity of Mr. Trump's Cabinet is just another example of political correctness run amok. The Cabinet heads are very important jobs and it simply should not matter whether it is diverse or not so long as they are highly qualified.
The misconception is that diversity alone is good. If liberals really just cared about diversity, they'd be happy about Ben Carson and David Clark and Nikki Haley are involved with Trump. They're not, so the point is that policies matter more than simple diversity. Trump is ignoring qualified women and POC, but it's not like that's the only thing that matters.
Donald Trump has selected the least diverse cabinet of any president in recent decades. Nearly all of his appointments are white men. Moreover, there is an astounding number of billionaires among his cabinet picks. This sets his cabinet up to represent only the richest and most privileged Americans--those who stand to gain more by destroying the government than by helping it function for everyone.
No, there is not enough diversity in Trump's cabinet. Even though there may be some token women and ethnic minorities in Trump's cabinet, there is not enough diversity as far as socioeconomic status or political thought are concerned. He has chosen many billionaires to lead departments, and his picks are mostly conservative.