Now, I'm not a big fan of Post-ROTJ EU, but it seems to me that what is portrayed there is a fairly satisfying and logical situation.
The Emperor is dead, as is Death Star, Vader, and at least a few key military commanders and the flagship of the fleet. Existing Imperial morale is devastated.
Rebel Alliance, with huge momentum after Endor, gain more allies and strength and go on the offensive. Open rebellions begin to occur (one way to interpret the SE added scenes).
Existing Imperial power structure, now free of the nigh unlimited executive, fractures as the powerful regional governors (and of course TRIOCULUS!) miliraty commanders and religious leaders engage in infighting further weakening the Empire.
Even if the Empire isn't magically instantly over, it was at least the beggining of the end (or the end of the beggining?). Major celebrating is in order.