But there are massive problems with Elm itself which make it impossible to consider seriously. I have and still do use Elm in production, and went through the nightmare upgrade from 0.18 to 0.19.
1. Elm ports are not sound. Elm will tell you everything is good but doesn't do simple checks - as say PureScript does - to see if your port code actually exists or adheres to the defined contract. There are other tree-shaking issues, but Elm does not know and does not care about the js you've written.
2. Evan holds the naive view that everything can be rewritten in pure Elm and there's no reason not to. An overwhelmingly common use-case is 3rd party services or tracking libraries where it's impossible to re-implement; these apparently don't exist.
3. Elm applications, without a Redux-style (domain-specific to Translator) pattern, end up being horrendous spaghetti code of everything knowing about everything. Cmds and Tasks are a pain to work with when they should be interoperable in some manner.
For small embeddable or personal projects Elm is a fun tool. I don't see it being more than that until more community involvement is permitted - removing the dictatorship.