Okay, so realize I'm not arguing for this at all since I haven't seen the movie since it was in the theatre!
But I thought it would be really cool if Reduction was the Solution because of the math! From what I understand of Nash's contribution to game theory, he proved that for a very broad set of "games" in which the players are choosing strategies to maximize their profit/return (while also considering the other players' strategies) there is something called the Nash Equilibrium. This is kind of a "stable state" that the game boils down to.
Note that although it's talking about "games" it's not really just games it's any non-cooperative scenarios with defined payoffs. A good example is a bunch of companies producing similar products, say wifi routers, and competing against each other. It turns out that even though they're competing, they will maximize their profits if they work together to create a standard for wifi, so that any computer will work with any router, instead of making the interface proprietary. (You can see both Production and Reduction in this example.)
So really a Nash Equilibrium is a solution that REDUCES all the possible strategies that players could use and all the ways a game could play out, down to one particular stable state (or a set of them I think). Imagine sitting at a table with 7 players playing some game, and somebody tells you that despite the big production of the game itself and all the possible ways it could turn out, the game is destined to reduce down to one scenario.
Definition of Nash Equilibrium (from Google dictionary):
(in economics and game theory) a stable state of a system involving the interaction of different participants, in which no participant can gain by a unilateral change of strategy if the strategies of the others remain unchanged.
Anyway, I thought it would be really cool if Reduction was the OS & MC Solution in the storyform because it would mean the writers sensed that dramatic force at work in Nash's life and aligned the story to the math.