Application Gateway needs to be faster and capable of greater transaction throughput
Currently, Application Gateway is the only service on Azure that supports offloading certificates for SSL, but Application Gateway can take a long time to provision and update with changes, and is unable to handle the high stress levels imposed by some apps. Application Gateway should be quick to provision and update after configuration changes, and it should be able to handle large numbers of requests per minute (e.g., 6,000 per minute).
We recently introduced changes which make any updates to Gateway complete in less than a minute. We are also working on reducing provisioning time. Regarding SSL offload performance – you should be able to increase the number of instances to scale out and handle increased load. 6000 new SSL connections per minute is not a lot and should be able to be served by a single Large instance. Please open a support ticket if you are seeing issues with performance at this scale.