Doesnt have to be a direct port of the console version, a mobile Halo game set in the universe with its own plotline that ties into the full version would be fine. That way it could be designed properly for WP7 and would just need to have certain elements from the full game like the iconic theme, some signature emenies and the assualt rifle and pistol. Bring out the next installment on better hardware and add Warthog races, MP, etc. So much they could do with the Halo universe on WP7, they just dont seem to have the vision to do it.