Some things were bad ideas but we never really figured out why they were actually bad. It’s easy to incredulously state “of course it’s bad because X” but it takes some deep analysis to really get closer to the core of things. Sometimes the results are not what you would’ve expected at all. Sometimes it feels obvious in retrospect.

And then some ideas are actually great, but the execution of the idea was poor. This can really make it seem like the idea itself is bad or impractical even though it’s not.

Personally, I liked E4X. Its probably better off gone, but I think the idea wasn’t so awful. It sounds bad in retrospect, but I used it and it was far from the worst way to interact with XML.