I'd personally prefer to see the "Entry" sub-window removed altogether and the previous pop-up window restored, though your suggestion of a double-click activation is quite good, and would solve the worst of my frustration with this "update"...
The things I dislike most about the new address book (aside from having lost ALL my mailing lists in the "update") are:a) If I click on a name the name details pane appears and obscures much of the rest of the addresses that I'm probably wanting to <...