[cptwunderlich]

That's not really true. There was a huge outcry against the removal of (/=). There are still lots of warts in Prelude and base (head being partial, foldl is in prelude but not foldl'). So yeah, language evolution is still a hard problem

[WJW]

You are right that it's not "really" true, but I do think that at least it's not wholly untrue. Foldable/Traversable got through, and so did Monad Of No Return, the Functor-Applicative-Monad Proposal and several more that I can't name off the top of my head. It does happen, even if we both would like progress to be quicker and more drastic :)

IMO, the existence of the Haskell Report and the inability of the community to update it in a reasonably timely manner is the biggest cause of the persistence of the biggest warts like partial head and foldl. I don't think anyone wants to keep those but "The Haskell Report specifies that they are in the prelude and with the exact implementation they have" tends to kill any discussion. Let's hope the HF makes some progress on that soon!