It is not optimal, but frankly, it is much, much more better than vainilla civ 5's civilization list, certainly an improvement.
For all the cries about eurocentrism in civ 6, in civ 5 we got a game that included the Sioux at the expense of the Incas and the Mongols, and that included the Soshone and Venice at the expense of the Khmer and Thailand.
I would gladly take an eurocentric list of relevant, well designed and represented civilizations over a "pandering to american tastes" one with a bunch of poorly represented civs (warmongering Japan, uber-generic America, and a long etc).
That being said, there's still a lot to critisize in the current civ 6 rooster. There are many big civs which really ought to be there (Incans & Mayans comes to mind), some reaaaaally obscure ones whose inclusion is truthly puzzling (Brazil so early?), and the S-E Asia region has got whoefully underrepresented,which is a pity considering how much of a rich history that region has.
However, the leader selection is incredibly spot on (save for Ghandi, ahem), and the design of each civilization has, so far, proved that Ed Beach has a far more deep understaning of history and what shaped each civilization personality than the designers of civ 5.