PoW at least provides a decent and somewhat fair coin distribution mechanism.

With PoS, the coin creators can assign themselves an arbitrary fraction of the coins, concentrating the wealth. Even if there is a public record of all the funds raised in a public sale and all expenditures made (which is rarely the case), it's possible for the creators to participate in the public sale and recover large parts of funds used to buy their own token by generous expenditures on software development and such.