Don't see your point, really. You're effectively arguing that the 2003 side was more dominant because of things that happened outside the tournament. We're talking about results in a World Cup here, not some sort of general analysis of the strength of a team. Australia have thus far dominated every match they have played in. The closest any team has come to beating Australia was a side who were chasing over 350 and had a good start. In 2003 there were a lot more challenges, and I don't feel the opposition overall was any better. Still two games to come though, so we'll see how those go.
For what it's worth, Ponting, Symonds and Hayden are clearly better players today than in 2003, Clarke is better than Martyn in ODIs, Hussey's amazing record probably cancels out the huge loss of Bevan, or goes close, Bracken's a big improvement over the likes of Bichel and Tait's more or less done what one could have reasonably expected him to do, which is take a lot of wickets. Watson's better than Harvey with the bat too, and the Symonds/Ponting/Clarke/Hussey group in the field is one of the best ever assembled in an ODI team. The team in 2003 had some stronger points, mainly the inclusion of Bevan and Lee, but it had more holes in it than the current one IMO, particularly with the bat and in the field. Bowling you could argue, certainly.
Anyway, the real point is that the team in 2007 has clearly been much more dominant and challenged a lot less up to this point in the tournament. Whatever the reason for that is, the facts are there.