As of ArcGIS Enterprise 10.8.1, Portal can be configured to hook up to an SMTP server and send emails for Password Resets. That's great, but there's a pretty big oversight here. The emails are plain text. No images, no branding, just words on a screen.
There's needs to be a reasonably well featured application to allow org admins to create branded, mobile responsive emails, preferably with tracking analytics of who read it and who didn't at the least. Simple read/not read tracking is pretty easy via tracking pixels that could quickly generated by and downloaded from the Portal server when an email is opened.
We should be able to create multiple email templates and send them to users automagically when certain events occur, which could be done by triggerring the sending of an via Enterprise Webhooks. Exmaples of some useful emails Administrator's could craft might be:
Welcome Email: Sent to the new user when the user_added webhook event fires.
Added to Group: Sent to the affected user when they are added to a new group
Removed from Group: Sent to the affected user when they are removed from a group
Role Change: Sent to the affected user when their assigned user role is changed. A different email should be able to be created for each user role (including custom roles) so that the Administrator can craft the email sent to contain information that is relevant to the newly assigned role (ie. Your assigned user role has been changed to Publisher. Here are some things to know about this role...)
Privilege Change on Assigned Role: Sent to all affected users when a change in privileges is applied to a role
Goodbye Email: Sent to affected user when they are removed from the Portal
This could also play into Esri's desire to introduce webhook events for updates to feature services. Then, on a Portal Item's Item Details page, a user could "subscribe" to an item via a button, checkbox or toggle that said something like "Notify me when this item is updated". Esri could go even further with this and allow users to receive daily or weekly emails of changes made to the service all in one email, a sort of digest if you will..
It would also be great if any bouncebacks from the SMTP server due to email addresses not being found could in turn offer the Administrator the ability to remove the user from the organization.
There are so many great options that an application like this could support in combination with webhooks, especially if we could use things like arcade or expression tokens to fill in usernames and other information in an email.