Things will probably change significantly next week, but I was curious to see at this point in the competition which picks were "necessary" ones, in that your team could not be competitive without them. To do this, I looked at the top six teams, which have distanced the rest of the field.
There were surprisingly few riders on all six teams, just Boonen, Pozzato, Peter Velits, Rogers, and Breschel.
These riders also happen to be five of the six most popular picks overall, which suggests that their presence on all six teams might in part just be coincidence (though both Boonen and Rogers are arguably "necessary," based on their success this year).
Riders who are present on five out of the six top teams are: LLS, Talansky, Demare, Davis, Iglinsky, and Sicard.
One of the riders I would have thought most likely to be necessary, Moser, is present on only three of the top six teams (although these are three of the top four).
All in all, it suggests that, a few riders aside, there are still a lot of ways to get near the top.