Should the Trading Deadline Be Moved Back?

For as long as I can remember, the July 31st trading deadline was one of the most exciting days on the MLB calendar. What often occurred at the trading deadline set the bar for the rest of the season-what teams would compete, what teams would tread water, and what teams were in full selling mode ready to deal away any valuable trade chips in the hopes of success in the future.

But for some reason, the upcoming 2009 trading deadline is beginning to feel watered down. Even though there is still almost five weeks to go until July 31st, the big time trade chatter has been kept to realistic minimum as virtually no big names seem to have a realistic chance of changing addresses.
And the reason why? Mediocrity.
You see, right now there are tons of teams (25 by my count) that have a cautiously optimistic chance at making the playoffs. Hell, even the Nate McLouthless Pirates are only 8 back in the NL Central and 7 back in the wild card! You can't fault a GM for holding off on becoming sellers on the open market when their team still has chance to play October baseball.
With so many teams having a puncher's chance at making the playoffs at the moment, there are very few teams on paper right now that appear to be clear cut sellers. Teams like the Nationals, Padres, and Orioles have virtually no shot at making the playoffs in 2009 and could benefit greatly by acquiring young pieces at the trading deadline.
However, because there are so many buyers on the market right now and so few sellers, the players who are available can only be had for a king's ransom. For example, if the Mets wanted to go out and trade for Adam Dunn right now, they would have to give up a boatload of talent because Dunn is one of the ONLY impact bats who could actually be traded for. Obviously, it's very difficult for trades to happen under these conditions.
In conclusion, having a bunch of mediocre teams might be very good for baseball and might make Bud Selig feel very good about himself for a few minutes, but mediocrity is actually very bad for trades.
So what can be done about this? One option is to move the trading deadline back. If teams have more time to separate themselves (either positively or negatively), then there will be more sellers in the marketplace because teams probably will not be as bunched up in the standings. I think the July 31 date has worked for a long period of time, but moving the non waiver trade deadline date back another two weeks or so should lead to more impact trades.
Thoughts?