Folders on top
I use my email to do email. I never use it to look for files. Why would I want a list of Files at the top of the screen? Why are my actual email folders (you know, like my Inbox) hidden below this? I close the Files list but, of course, will have to close it again next time and every time. I understand I could simply look below the file list, but I shouldn't have to. This is stupid interface design choice. What comes next? Putting my Junk folder above Inbox?
The Favorites list is on top, but that's fine, because it's closed by default. The Files list could do that or (much better) it could be stuck at the bottom, as it's used way less than everything else in Mail.
Melissa Beth Lowry commented
The entire "Files" feature should just be removed. I am in agreement, I don't use email to work in Excel or Word so having the template there is the most useless thing thought up so far. And worse even than that useless feature is the placement and the fact that it will not stay collapsed. It expands every single time I open my email, which is just beyond irritating because I got to my email for EMAIL.