To be as objective about it as I can be, I'd have to say declaring victory at 2025 is purely a PR move. It's the moment he passes half of the official delegates (at the time) and combined with a handy win in Oregon will give Obama a big boost and put the loses in Kentucky and West Virginia behind him.
Then the DNC rules committee will approve a plan both Clinton and Obama can accept to seat Florida and Michigan, which will likely be half votes for all their delegates and some compromise on the Michigan split (and in an ideal world none of the supers, to ensure this doesn't happen again and punish the people responsible, but that's neither here nor there). This bumps the magic number up roughly a hundred and puts Obama below it again, but the writing on the wall will be even clearer then than it is now and the pundits will talk more about how this clinches it for Obama than his jumping the gun claiming victory.
Finally, combine the continued super movement we're likely to see with the probable Obama wins in Montana and South Dakota and he makes up the delegates won in Puerto Rico (which Obama might even win) and Obama passes over the new magic number and declares victory again.
The short version is claiming victory now lets Obama control the narrative for the rest of the primary season, and lets him "win" twice at no extra cost.
They are not good reasons for the Party to nominate someone who attains that number.
Screw it, why bother with primaries and delegates at all if you don't nominate the person who obtains the official number? Why not just flick a coin or give it to Clinton?
The serious answer is we hold primaries and caucuses to obtain valuable information about the voters and the candidates, and we would be wise to consider all the information we obtain in the process - not just the information which favors one candidate and/or ignores some voters.
Yes, the Democratic Party makes rules and sometimes breaks rules. Rules are important, but they aren't always good for us, and they should never be allowed to cripple our nominee by enabling their nomination with less that a majority of the Party behind them.
I see no good reason to award the nomination to Hillary Clinton unless she manages to get the support of at least 2,209 delegates at the National Convention. Likewise for Barack Obama.
You are hilarious - in a banner year for dems, highest turnout in years for a primary season, two great candidates, you think we should nominate neither? Hilarious.