> On top of that, the spec was massive, included a lot of kitchen sink style accumulation of language features - I can’t recall which feature it was, but I do r

> On top of that, the spec was massive, included a lot of kitchen sink style accumulation of language features - I can’t recall which feature it was, but I do remember when some language showed a new feature it was almost immediately shoehorned into ES4. And in very many cases, too much was added too fast: the spec was _miles_ ahead of any implementation. You really don't want the spec getting too far ahead, as so many issues only become obvious during implementation, and you don't want to be building indefinitely on top of that potentially unsound base.