ok my theory is that the final scene of the last episode had to go 3 ways,
1) the guy going to the toilet is a obvious nod to 1,but that would be a cop out to end the show that way.
2) Meadow running late could be a nod to godfather 3 where the assassin goes for michael but gets his daughter,in the sopranos case the assassin goes for tony but gets the entering meadow as she can see the assassin coming up behind tony
(tony is sat facing the door,a nod to goodfellas the always sit facing the entrance or by a window)
3)the feds could be entering to arrest tony when he is least expecting it.

if tony isn't dead he is now boss of new york as it is obvious that carmine jr will take over new york and carmine jr is really tonys puppet.
In the sopranos book chase said those expecting tony to die face down in his onion rings with a bullet in his head can fuck off.