[bonobo3000]

I'm not totally sure how a blockchain works so please correct me if im wrong - for a hard fork to happen in Ethereum or Bitcoin, the majority of users have to "agree" by switching to thew new blockchain right?

In that case, the Ethereum hard fork doesn't sound very controversial - even if the devs decided to hard fork for bad reasons later on, no one would be forced to adopt it. They would be "voting with their feet" by sticking to the old chain.

[anonx]

That's the case if there are dozens of different client implementations each maintained by a separate independent team. If there is just one client and no people qualified enough to fork it and maintain we end up with a centralization. The only team can make whatever changes they wish.

[DennisP]

Ethereum currently has eight implementations, each in a different language, some independent of the Foundation. At least the Go (official), C++, Rust, Python, Java, and Javascript clients are full implementations. The Rust version is especially nice; it's the fastest, and produced by an independent company run by one of Ethereum's early developers, who no longer works for the Foundation. (The Haskell implementation has fallen behind, and the Ruby one is pretty new, I'm not sure of its status.)

It's relatively easy to make an independent client because there's an actual spec and a test suite.