Does the drawn-out primary season hurt the Democrats?

There's been a lot written since Tuesday on whether what will now clearly be quite a drawn-out struggle hurts the eventual nominee.  The academic research on the issue essentially says, “no.”  Salon's Walter Shapiro argues that it is good for the Democrats:

But the problem McCain faces is that he still has a faceless
opponent with the Democratic race far from settled. So, in effect,
McCain will be shadowboxing against a vague entity called
Obama-Clinton. The result is that (just wait and see) McCain will find
it difficult to make news since there is no longer any drama to
anything that he does until it becomes time to pick a running mate. The
Project for Excellence in Journalism,
which monitors media coverage, found that last week the Democratic race
generated four times the attention of the Republicans. And that news
blackout occurred when McCain still had a nominal opponent in Mike
Huckabee.

So rather than fantasizing about a soporific and conflict-free
nomination fight, the Democrats should recognize the value of what they
have stumbled into. The contest between Obama and Clinton — this
battle of historic firsts — has the entire nation hanging on the edge
of their seats. Who with any sense of show business would think of
pulling down the curtain when the audience is shouting for more? But,
then, if the Democrats had any sense of what the public craved, George
W. Bush probably would not be in the White House.

Yet, I find the logic of this Ross Douthat post the most compelling:

Rather, the problem is that the party is losing a golden opportunity to
try to put the race away early, the way Bill Clinton more or less did
with Bob Dole in 1996 – by using their enormous fundraising advantage
to rebrand John McCain as a Dole-style loser while he's still
struggling to get his money-raising operation up to par. As Patrick Ruffini suggested
earlier this week, if Obama had finished off Hillary last night he
could have been up with anti-McCain ads all over the country
immediately, forcing the GOP to play defense in places it usually owns
all through the summer. Whereas the longer the race goes on, the less
leverage the Dems' fundraising edge gives them, and the lower the
chances that they can make it get late early for McCain through sheer
dollar-power alone.

Of course, we'll never really be able to know what the impact is.  As I always say in classes (to funny looks), if only we could also see what happens in the Star Trek universe where Spock has a goatee to see how things might turn out differently if the Democratic nomination battle had ended Tuesday.