I regularly listen to audio files in Evernote on iPhone. When I get a call, or have to pause for a few minutes, Evernote does not remember where I was in the audio and usually restarts the app.
Whether it's a voice memo I recorded with the app -- or a 1-hour seminar .mp3 I've purchased -- it's more often that the audio is at least 1 hour in length. I try to listen in one sitting, but it can be difficult.
Right now, the iPhone app will crash or reset if I switch between apps or lock my phone for a few minutes -- so I usually try to write down the audio position so I can return where I left off. But if someone needs to talk to me -- or I get a phone call -- and I don't get the opportunity to write down the timestamp, losing my played last position.
Having a "remember playback position" would be a HUGE benefit and wouldn't require a new interface.
Beyond that (this may require a change in the audio interface), it would be helpful to have a playback SPEED option (1.25x; 1.5x; 1.75x; 2.0x) to get thru audio that is sometimes slow. Right now, I have to be on my desktop or laptop and export to VLC to use the "playback speed feature" -- but having this available in the Web App, or iPhone App would help me process and listen thru longer audio where there are long breaks of silence or slow speaking.
To dream a little bit... it would also be cool to have a keyboard shortcut available on the Mac App for playback pause/play, and speed to be able to power through audio notes more efficiently. In Premiere Pro "J" "K" and "L" are used for Rewind, Play/Pause, and Speed up respectively.