I could honestly see Halo 2(at least the mp portion of the game) being free to play on Xbox One. It seems like -Yoink!- and Sony are both trying to push the popular F2P models used in PC gaming onto their new consoles. I’ve just been trying to think what they could charge for. Their is always a catch with those games and they always want you to buy things.
If they remaster the graphics they could make the MP free and charge for cosmetic items like armor and emblems. I would just love it if H2 was F2P, not because I don’t want to pay for it(because I would pay a ton) but because more people would be playing it.