In terms overall productivity; extending the competition should have net positive effect because it prolongs the race condition that's fueling the participants' motivations, no?

The main downside is that this would be seen as unfair, by anyone with limited time/plan/strategy that can't take advantage of the extended time to raise the value of their submission along with the rest of the competitors.

ps: i'm pitching in too... a little late, but I hope it's still accepted and useful.