I would love to see the SEND / DELETE Buttons on top. If you receive a long email, more lines than screenspace available, the buttons SEND / TRASH … are hidden at the bottom. You have to scroll down to get to the SEND / ATTACHMENT / TRASH buttons.
Therefor, i would like to see them on top of the email, above or below the To: From: fields
You can try my theme. It has a git branch feature/top_buttons that moves the action bar to top of window and reverses the button order (so primary button is always on the right).
It has some drawbacks: It looks odd and the tooltip popups for commercial features are off as they are hardcoded