Effectively everyone who's mining controls Bitcoin. They decide which rules they want to be enacted.
This is not true. Every user that runs a full node decides which rules will be enacted.
If they do enact rules, other miners (the majority) don't approve of, their chain gets abandoned and thus effectively is being ignored. It's merely a matter of what the majority decides to accept.
This is not true. Bitcoin is a system that relies on the consensus of the users, not the majority of the miners.
That's the beauty.
The beauty is that the miners can't change anything about the core protocol without the consent of all the users.
The core developers come up with new ideas though, and also implement them. But if the miners don't approve of them, they won't be enacted.
And if the users don't approve of them, then they won't be enacted (even if the miners do approve).
The miners add new blocks to the block chain, so unless we change that paradigm, all that full nodes can do is withhold transactions or modify them in some way. That's it.
