Idea for the Half Life finale (no spoilers)

I thought it would be a really a good finale for the half life series, if the G man is a boss who has taken alyx hostage, and Gordon fights him for his freedom. While their fighting they keep materilizing in places important to gordans past such as black mesa, the streets of city 17, the city 17 train, the cithadel while its frozen... those sorts of places. And when he defeats him, such as the G man is hanging onto a buildings edge on top of the cithadel he should say something for the first time in the games.. something like "Im done with you" and let him fall to his death.

What do you guys think?