Possibly, but I think you're missing the point a bit, which is that whatever new QB was chosen wouldn't realistically be able to step in and actually lead us to a handful of wins should Brady go down for 4-5 games in their very first season. One would think that if Belichick were actually considering trading Mallett, that he would have had brought in another QB last season--even if that were a PS QB. That would have allowed us to have had someone who was at least familiarizing themselves with our scheme and playbook.
After all, aside from the gamble BB took with O'Connell, there has never been a backup QB who hasn't had at least one full season under Brady's tutelage; more important, there hasn't been a backup QB who probably even had 1/4 of the playbook down pat in under a year, particularly in this kind of complex offense.
In other words, it would make zero sense (not trying to question or disrespect you) to swap out QBs for the 2014 season, although it would be obviously beneficial for the longer period of the future.
If Belichick trades Mallett, he'll be gambling a lot and leaving the all important backup position wide open. That seems awfully un-like Bill Belichick. Many have pointed out the fact that it wouldn't matter anyway since we won't go too far, but it could matter if Brady went down from weeks 5-11 or something, as it could cost us a playoff spot, etc.
I think this is one of the reasons why Belichick is pricing Mallett so high with a 2nd round pick. That seems to be what it would take for him to be willing to make such a gamble, as it'd be too good to pass up.