Yeah creating a game engine to keep up with the all the different fascists of the game is almost impossible, and keep it as sharp as you want it.Oh I see what you mean. Would still probably increase some sales, but the game itself will still need to be good, and that won't improve how the gameplay is. Don't think giving or paying someone else to take the license would work, as the AFLPA would want money to use players likeness and names.
Us fans get frustrated enough with the annual rule changes, but imagine trying to build a game where you need to change the game engine all the time. It's hardly a recipe for a good game.
Other choice would be releasing a licensed Coaching simulator, much like Football Manager in the UK. Where you don't play as the players but play as the manager make changes, adjust your lists depending on needs etc. Wouldn't require as much investment or Game Engine building, but wouldn't probably have the wide appeal of an AFL version of FIFA.