But for a Halo game that fall in players is shocking.
Killzone has always been a B grade shooter compared to Halo, Battlefield and CoD so it isn't surprising it doesn't have a high number of active players.
However with Halo being MS flagship series and the amount of money and promotion the Halo brand receives, then that kind of decline in numbers is indicative of Halo 4 not being well received by players at all and they are more interested in BF and CoD.
Strength is the only thing that matters in this world, everything else is just a delusion for the weak.
What's funny is that the PC version of Halo CE is still among some of the most played FPSs even today. I personally think that Quake and Unreal are more revolutionary games, but Halo is fun nevertheless.