In order for a sequel to feel like part of a larger story and not be seen simply as a sequel, it will need to contain plot information which is absolutely essential to understanding the nature of the primary conflict, information which was not in any way present in the original movie. In this way, ESB excels...
What you say is true, but I can never bring myself accept the way in which ESB does it, as the big reveal is the point at which the shrinking universe that so plagues Star Wars really kicks in. Your conception of how your Episode VII will function within the series is undeniably well thought out though.