I think it should be a game by game basis.
Cd project red or Bethesda for rpg
Treyarch, or 343(if ms went multiplat)
Naughty dog for action game, although I think respawn is going to surprise people in this regard.
Halo MCC will sell 5+ million copies(including digital)
halo 5 will sell 10 million copies(including digital)
x1 will pass ps4 in USA, and UK.







