Those are some pretty terrible reasons, and in all honesty: They shouldn't continue the franchise.
They already have made an incredible amount of money and have gained much popularity off of this trilogy, you don't want to keep going and milk it out. There's a point where you cross the line of dignity.
First , no horrible reasons as the guy said and second the Halo movie was cancelled due to money shortage or somethinng. Halo 4 shouldnt be made. 3 is enough, they've become a well known now. Plus they might make another sequelish game that might be better than halo [ they wont EVER create a better main character than master chief ]
Isn't Halo 3 Recon coming out soon 2?..I agree enough is enough...Halo 3 and Halo Wars...experiment with something else. Although Master Cheif is an awesome Main character.