Halo Reach #4 as of Sept 19, 2011,
Halo Reach released Sept 14, 2010.
Halo reach did not end up at #4 until a full year after launch, say what you will about reach - it proved to be more fun then Halo 4 for most people AND was not pushed down by a year old title but by a newly released GoW3.
343, your going to have to do a lot more then a TU to save Halo 4 and Halo 5&6.