When browsing emails every time you hit the end of the list missive has to load it again. Its better if there is an option to store the emails like outlook does.

Please add the ability to merge emails/conversations by drag and drop.

Would be nice to be able to have Google Calendar as part of Missive so that I do not have to keep a separate window opened to view my calendar.

The ability swipe/pull down inside an inbox to sync. Although the app may be push, I want to ability (even if just perceived) to sync myself to it feels the most up to date in that moment.

I would love to be able to trigger actions from conversations, assignments or emails received from a certain address to notify Slack or update a line in airtable or on a google sheets (amongst the million other things you could do with Zapier).

I would like to be able to remove myself from a conversation.

Being able to manage WhatsApp would be super nice :)

Handle .ics event invitations and responses with shortcut buttons (Accept, Refuse, etc).

It would be tremendously helpful if, when selecting a tag in the left side bar - that all tasks connected to emails within that tag were displayed in the right side task bar.

It would be nice if we could enter the name of a contact book in the 'to' field, so that all the contacts in there will appear.