there is no way to automate the "Flush Cache" ability in MWG directly.
MWG 7.2 will allow to trigger this action via the REST Interface, so you could write a script that automates this process.
Was there a reason why this is manual ( or script solution) and not a necessity of the appliance design. As a customer, what can I do to ask for this to be a feature on next design?
The reason for not having an automated flush of the web cache is that the cache should manage itself. The cache will remove old entries when it's getting full and a manual intervention is usually not needed.
If you want to submit a feature request for this you can use this form: