Allow usage of different SMTP Configuration in Workflows
You can create multiple SMTP Configurations but you cannot select different ones in workflow email tasks, you should be able to from a dropdown select which configuration you wish to use for that task, or at a workflow level select it as well.
Tom Humphrey commented
This would be tremendous.
Also while you're at it, please add in the other fields that are "built in" to the email standard like BCC, Send-As and Reply-To.
This would allow us to do some really powerful things using customers existing (reliable) infrastructure.