Would there be a consideration to have a method to sort emails via 'unread'?
I don't think it'd make sense to have a view just for unread items, but there is definitely a use-case for having unread items grouped together.
Rationale:Date/time of message received isn't always the most effective - for instance, I might have opened a less important email on my mobile device. I may not have taken action on this email (file/reply/delete) therefore it sits in the 'work queue' a.k.a. inbox waiting triage.
Use-case: I've gotten up late, my boss is in a bad mood because I haven't read all of his numerous emails. At this point, I want to be able to 'blitz' through everything which is unread in a focused way, forcing me to do triage the data in order of importance.
Perhaps then even a view which could simply allow the user to focus on triaging the data with criteria like:
-Needs info from X
-Can wait (the email from my girlfriend asking me to review the shopping list can wait, but then also not infinitely), so then this could be placed somewhere which says 'Needs action - but less critical'.
All this to say that large volumes of data can sometimes be overwhelming, if you don't triage as you go along or just get lots of emails.
It may help some users to have a system which can help them to work in order of criticality.
Is this in scope?