Confirmed via a message from the Saints: "We do understand your point that we have 1 less game with the London game, but we sell the season tickets as a package."
The Saints get fully compensated by the NFL for lost ticket revenue from missing a home game PLUS a $1 million bonus. Then they charge the fans for the full season as if we didn't lose the game at all. And they invoice people as a "package" - instead of including individual prices for each game they way the used to do - in a very obvious strategy to hope people won't notice they're getting screwed.
My tickets went from $115 per game to $135 per game. That's an 18% increase.