Governance, no… But transaction selection?
Some other PoS systems use delegated proof of stake, where most people just delegate their stake to one of a small number of validating nodes, which could easily cooperate to censor transactions. Ethereum supports a very large number of nodes, due to signature aggregation. Right now there are about 400K individual nodes. Entities of course can have more than one node, but the last estimate I saw of the number of individual entities put it at around 5000. (That was at least six months ago.)