Do you actually NEED a download all button?
Unless you're flying a Citation around the country probably not. Remember it costs the OZRunways guys for bandwidth and will keep costs down if you only download what you need.
A better idea might be a "favorites" option where you select the maps you want once off and it downloads those ones each time a map update is required.
Ditto on he attitude of these guys. No empty promises and airey-fairey ideas on something that will never come to fruition.