I suppose you never have to use closures, since you can always rewrite to use defop. But a major selling point of Arc seem to be the conciseness of building flows using macros like w/link. If this approach turns out to be not recommended for "real world use", I think it defeats the purpose and it would be fair to say that Arc itself fails the Arc-challenge.
I'd much rather change the underlying implementation of w/link to be more robust, if possible.
(Btw. it is only in the context of links I think long-lived closures are a problem. In the context of responses to form posts I don't think there is a problem, since these are not bookmarkable or indexed anyway.)
