I know the meaning well, shame when it happens - but every series seems to make the effort to squeeze either another season or better ratings and story-lines by doing it. Rarely does it work out. Adding new characters or swerving away from your plot is almost always a last ditch effort. I don't know why the Soprano's needed this, but frankly the last two seasons were CRAP - except for this last week's show, the others were all pretty good. When you are counting down the episodes and shooting dozens of endings WITHOUT cast interaction to "Protect" the ending, continuity surely falls apart - let's hope they save the best for these last two episodes starting nex week.
In Heroes, the Father of the Cheerleader was suppose to be a bit character, but turned into the most complex of all and is written into all shows - I guess this isn't Jumping the Shark, but it surely an example of what SHOULD happen in a show.
P.S. I still hate CBS for cancelling out Jericho - freakin' idiots!