The commentators all seem to think that it is some horrible thing for the Democrats that they are still fighting it out while the Republicans have it wrapped up. This is just wrong. In 2004 the Democrats wrapped it up much to soon -- while the primaries were being contested there were all the candidates beating up on Bush and being covered. Once Kerry had it wrapped up, it was quiet until the convention and Bush was rebounding.
Everything is so front loaded that we forget that we are still fairly early in when candidates have their nomination wrapped up. Usually most primaries wouldn't have happened by now. The period from whenever the nomination is decided until the election will be plenty long.
Finally, having the eventual candidate have to campaign in all these states and build organizations and generate the level of excitement this generating is going to a huge help going into November.