Like this: http://evancz.github.io/elm-architecture-tutorial/examples/7... ?

Yes ... but with a more natural implemention. That style won't scale up to real dynamic programs though without significant routing infrastructure outside of Elm's typical constructs.

Naturalness as a criterion for evaluating languages is not that compelling to me. I think a honest word for what people usually mean when they say "natural" in this context is the word "familiar". I know plenty of programmers who think that OOP is just more "natural" than FP.

What I really would like to see is a counter example. Some GUI that just can not be done in Elm.

> What I really would like to see is a counter example. Some GUI that just can not be done in Elm.

I'm on the Elm/FRP fence myself but your comment here reeks of turing tarpit:

"Beware of the Turing tar-pit in which everything is possible but nothing of interest is easy."

Without going on too long a tangent, this hasn't been our experience in practice at NoRedInk. We've built some absurdly complex UIs involving those same design needs, and what you're describing just has not been a problem.

I'd suggest giving it a try. It's really nice. :)