1. A refresh button that does a POP fetch from other accounts. Currently I have to go to Settings > Accounts and then click fetch, and if I don't do this on an active email thread things get messy with replies to outdated messages.

2. A small one-click popup note feature. When I need to jot down something quick I write it as a new message and save it as a draft to come back to later. Or if I need to upload a document to access from a different computer I'll do that in an email draft as well. It would be nice to keep that kind of thing separate from actual email but close enough to be just as convenient.