To people saying pre-ordering is pointless your wrong it has two major incentives.
1. You get the pre-order bonuses which often times are pretty freaking sweet. Like how both Assassins Creed and Battlefield 3 get autoupgraded to the Collectors edition just for pre-ordering.
2. You can use it like layaway that way you don't have to drop $60 at once and can just put like $10 a week down on it till it releases
but either way OT trust me MW3 will crush any exclusive PS3 game this holiday so that is certainly not the reason why numbers seem low for MW3 on PS3.