I think the change from series to movies might be explained, if at all, as being in large part a cascading outgrowth of Picard's experiences with the Borg (and maybe Gul Madred), first in the series, and then later in the films. To get back to the original point of contention, though, the whole appeal of the Nexus for Dr. Soran was that it creates a sort of alternate reality based off of one's fondest desires, and when Picard ends up in the Nexus, we see him surrounded by dozens of children and grandchildren...