The quickest thing to ruine casuals is to put them into a game that splits the screen 4 ways.
With XBOX not being high def... Casuals already get 1/4 the res... and then they occasionally forget which corner is their 'screen'.
Trust me... you dont want to put casuals into a split screen game... let alone a FPS.
whats wrong with splitscreen.
Your screen is split in mariokart/blur hell nearly every single 4 player game out. Even you Guitar Hereo and music games are splitscreen,
I think you may be confusing Casual Gamers with Gaming Illiterates.
TimeSplitters split screen FPS
Mashed - Micro Machines styled racer.
GTA:SA - always fun
V8:Supercars 3 split screen racing
Super Monkey series similar to mario party.
Rayman Ravin Rabbits - Similar to Mario Party
Red Faction splitscreen fps
Worms 4 - turn based cartoon worm killing
Lego:Starwars/Batman/Indiana Jones/Pirates - i enjoy these