one thing past halo games and gears of war did really well was multiple enemy variants instead of shooting the same thing over and over again. Since there is going to be new threat (forerunners, precursors?) what kind of enemy variants do you think we will see??
normal forerunners
Sentinal Enforcers again
Sentinals
Moniter?
Larger forerunners seen boss style
promethians as bosses.
Brutes (the forerunners use brutes as cannon fodder)