Well if you think about it, the whole game itself is essentially a well-made, and overpriced mod. It uses the same game engine as Battlefield 2, but has more "futuristic" things like Mechs and guns that shoot alien-like bullets or whatnot and some nice customization options. Then they slap a $50 price tag expecting you to eat it up like it's nothing.
Battlefield 2 was the first Battlefield game I ever bought, and if EA keeps things they way they're going, it'll be the last Battlefield game I'll ever buy.