I really think the tutorial should be structured, as you're going to need that structure to fully understand the game without the bizarro happening. (Or maybe structured for exactly that purpose - Sucked up by a tornado at the end of tut anyone? :D)
The other thing is that (In my own preferance) the character at the end of the Tut should definately die, as this teaches you how to play with everything, so starting with said everything isn't really fair.
This also expands greatly on potential, as you could then have the tut have any number of scenarios from escaping a crowded subway platform which zombies overrun, to having some clue to the backstory.
The tutorial is a little something called trial and error.
Yes, I agree.
As to the beginning, it would've been very interesting to be there to witness the fall of society, but I think it's too much of an undertaking for the developers, and so focus should be on making the best of what's realistically possible.
I know Zag said that we're not to decide what's too hard for them to do, but I'm afraid adding realistic AI crowds of non-infected will require too many resources.