Where does everyone expect the FW42 to be? Good enough to do what Sauber did last year? Progressively get better throughout the season?
2011-->2012 and 2013-->2014 were much bigger jumps towards the front of the grid than anyone had expected. Historically, Williams have a good record of big improvement after a horrible season.
You never know, though. F1 is not about your own job, but about how well you do compared to your opposition. Possible over and underperformance of other teams on the grid will have a significant bearing on where Williams will be this year and this is something that is very hard to predict.