I've been to numerous forums where people are upset with this functionality, but I haven't come across the real fix you're looking for. Until that functionality exists, here's the workaround I use:
Turn reading pane on with bottom placement and shrink the reading pane down as small as it allows. It doesn't feel like it's in the way, and I can single click through everything without losing my inbox view. And I can double click to open the email in a new window.
Hope this helps ease your frustration!