If we strip out ```handler``` from the closure function for the ```:on-error``` key, we could change the body of ```wrap-json-body``` to use:

``` clojure
(handler (on-error request ex))
;;=> and
(handler (default-on-error request ex))
```
instead of
``` clojure
(on-error handler request ex)
;;=> and
(default-on-error handler request ex)
```
Is that what you meant @weavejester ?