I have one feature request for the hierarchical folder selection:
I have a hierarchy of folders that is several levels deep. In current version, going deeper in the hierarchy is a little cumbersome, as I have to first select a folder, then tap "Open", then select another folder, tap "Open" etc.
Another email app I tried (MailDroid) solved this more elegantly. It provides a direct "open"-arrow for each folder in the folder list. Tapping the folder name selects the folder (like in Aqua Mail), and tapping the arrow opens a list of subfolders inside that folder. That saves 50 % of the taps needed to select a subfolder. I've attached a screenshot to clarify what I mean.
Matti