Sure but why would you have a Halo 2 mod when you could have a Halo 3 mod.
Because i hate Halo 4's graphics
And i liked Halo 3's dual wielding and certain equipments, which Halo Online does not have
Also, speaking of PC Halo,
Installation 01, still in the works, but is looking to be a pretty great from-the-ground-up fan-made Halo game