Some quick thoughts about the positive aspects of Halo (1,2+3) Multiplayer Design.
1) Social dynamics of team multiplayer raise the stakes without adding any rules.
2) Heavy emphasis on items and vehicles makes map positioning and tactics important.
3) Weapons are very simple and distinct from one another.
4) Grenades and melee attacks mean you always have options, and give you common skills to develop while you explore other weapons.
5) High health and movement capabilities mean that skirmishes have enough time to develop and establish a back and forth “dialog” between combatants.