I definitely agree, the golden days for halo was way back during the first 2 years of the xbox 360 release and obviously the original xbox, and yes i do know that xbox live was really terrible on the original xbox without halo 2 and i also do believe that halo 2 suits and feels right on the xbox.
PC was just not designed for halo 2 and whenever i play it, it does not feel as good as it did back then no matter if the keyboard and mouse has a better sensitivity for first person shooters.
Halo 2 was designed for xbox and that is what it is.