Without the subplot, though, there's no real reason for Anatoly to return to the USSR. Doesn't he only return so that her father will get released? I would guess they keep the subplot because otherwise Florence is defined almost entirely by her love interests, which does not an interesting female character make.
I don't know the Swedish version well enough (which rewrote the book yet again) to see if they managed to make the book any more compelling.
EDIT - so I've just read the Swedish Wikipedia entry on Chess. In that, the reason for Anatoly to return to the USSR is that the KGB use Svetlana and his children as hostages. He and Florence never actually become an item per se - they never get the chance, as the whole show takes place in Merano (there's no One Night In Bangkok in this production). Florence's father is missing, presumed dead.
Updated On: 5/9/12 at 10:44 AM