Minority of hostile dirauths can influence consensus in dangerous ways
We like to claim that if a minority of dirauths is not honest, the worst they can do is manipulate the voting process in such a way that no consensus emerges but not that a consensus emerges that is (at least partially) dictated by the bad actors. Unfortunately, this isn't the case for the opt-in features. If a majority of the dirauths opting in to features such as bad exit voting, bandwidth measurements, or voting for a specific parameter want to influence these values in the consensus, they don't require a majority of total dirauths to do that. This might not be so much of an issue with less important features like Naming, but since badexit and bandwidth weight directly influences path selection on the client, these authorities that opt in to those features have considerably more power over the consensus than those that do not.