Marcum was never perceived as having quite the high upside (though likely finishes with the best career of the group) and McGowan was already deep in injuries at that point, but Cecil/Drabek/Morrow/Romero were all high picks who were thought to have huge potential... similar to the Stroman/Hutch/Sanchez/Norris group.
Not sure how common knowledge this is outside Toronto, I'm guessing pretty well known, but Jays scouts all wanted Troy Tulowitzki at 6th overall in 2005. Then GM JP Ricciardi thought he already had a SS of the future in Russ Adams, so he overrode his scouts to take Romero