From my eyes, those individual competitors entering the Open will fit into a few different categories as to what I believe their goals should be.
Group 1 - these individuals know they are going to make it through to the Regionals 2012. The Open is merely a stepping stone. Their goal is the make it to the Games, proving themselves elite amongst the peers in their region. Their training will utilize the Open workouts as simply a "portion" of their week of training, nothing more. This is the time to begin building the volume of Lactate/Aerobic sessions in preparation to peak for Regionals (or, that's what I believe you should be doing). The individuals abilities/make-up will determine how, when, and where the volume/intensity should be applied to their training.
Group 2 - these individuals, myself included, know they will make it though the Open, but their goal is not to compete in the Games. Their goal is to do as well as possible in Regionals. They either know they cannot beat the top people in their region given their abilities relative to the demands of CrossFit...OR they do not take it too seriously, and just enjoy the competition/camaraderie. These individuals should follow the same idea as group 1 with regards to the training...depending on what their commitment level will be to increasing the volume/intensity of their training will determine the layout (usually read as, do they actually want to put their best foot forward, or do they want to be able to say they didn't train enough, or they weren't prepared, or what have you...they want an excuse).
Group 3 - for these people, making it to the Regionals is their #1 training goal at the moment. Once at Regionals, doing the best they can given the events/weekend against their peers in their region is what gets them up for the event. Their training should already be dialled in with regards to intensity/volume, in order to ensure they will be ready for the Open workouts and that they will peak at some point in the 5 weeks of the Open (preferably in the first 3 weeks).
Group 4 - being a competitor in the Open is all they really want to be. To do their best week to week, and to place as high as possible or higher than previous years. Their training should follow the same idea as Group 3, again depending on the commitment factor.
Group 5 - this individual is a first time competitor in CrossFit. They are still deliberating whether or not to even commit to competing, as they have a laundry list of excuses as to why they should not compete (I can't do muscle-ups, I can only do 1 HSPU, I hate sweating in front of others, or what have you). My position is that these people should compete at least once to experience the mental difference in knowing that your score will be placed against others and to actually test their physcial/mental/emotional fortitude. Winning is not what is important, completion is what is important. One thing I always try to have my clients understand is that they need to not "define" themselves, or to "attach" the results of the Open to them as human beings.
Group 6 - training is enough. Whether their abilities are quite good or not so good, they have no interest in competing.
One last thing, if you are reading this and fall into groups 1-4, and you do not have a knowledgable coach guiding you to your goals, then what are you doing?! You absolutely need a coach...end of story.