On your blockchain, if a new consensus rule is being disputed or if a bug in the consensus rules causes a fork, who has the final say, the developers or the miners?

We will likely use Cosmos which uses proof of stake validators instead of miners although we are prototyping on Ethereum. In any case, the miners/validators would decide, as they always have and always will. If there was a big divide between users and validators, the users could choose to leave and use a different fork (although they would have to modify their router firmware). The only power that the developers have is thought leadership, and the ability to claim that something is an "official" binary. This is also how the Ethereum DAO hardfork went down.