Even without talking about type classes, the lack of applicative is weird. I know: nobody understands what applicative is for, but if you have map and you are currying parameters, you're going to run into the issue ;-) Instead, you've got map, map2, map3, map4, map5 (which also, frustratingly, don't implement applicative). There are lots of validation scenarios that are just way more complex to do in Elm than they need to be.
But to be honest, it's fine because the language is not supposed to give you everything that you might want. It's geared for people who want a subset that's easy to learn. If I'm going to write code for myself in this space (functional language that compiles down to JS), I'm going to pick Purescript because it has everything that you're ever going to want. But if I'm choosing a language for my team that doesn't know functional programming and (to be blunt) doesn't really care to learn: Elm is a much better fit. They can learn just enough to get their work done.
But I just wish it was stated in those terms clearly. The premise of the article has been played out time and time again in the Elm community: "I thought this was a fully featured functional language, but when I tried to do this completely reasonable thing I got my hand slapped".
At every turn the response to, "Why can't I do X" is "Because you don't need to do X. It's much simpler to do without X" -- which usually isn't true. It's much simpler to learn something without X, but X is there to make your life much easier as long as you can deal with the complexity of learning it. It's the old "ease of use" vs "ease of learning" issue.
