Similar to how users can tag an email while composing a new one, users should have the ability to tag a discussion while composing one, especially since you can do it after the fact anyway.
Always include option not to send attendees an email about an update made to the event
Today the option to "email guests" about an event change is only available sometimes. Needs to be available consistently for all types of event updates.
Ability to select multiple attachments to drag/drop to desktop or other app
Right now you have to select or drag/drop one by one to move attachments to another system or your desktop. For conversations with multiple attachments, this can take several extra clicks.
Use Microsoft Teams as video conferencing option when using Gmail channels
Right now it seems video conferencing option is limited by what channel type you use for calendar. It would be awesome if this was independent of the channel type for calendar.