Google announced through Google+ today that Gmail on Android is receiving an update that includes a couple improvements all based on user feedback.
For one, you can now tap on contact avatars in emails to see a full history, including recent conversations, contact info, and more robust details about the person should there be a Google+ account attached. Items like people you have in common, recent G+ posts, their birthday, place of employment, etc. can all be in there.
The update also includes an improved account adding experience for those using non-Gmail addresses.
The update is rolling out slowly as usual, but you can sideload the newest .apk below.