What I meant by diversity of gameplay is, for example, you can play most of fallout 2 never fighting period, using your charisma to navigate the game. Or in almost every D&D crpg ever made you could play a thief class, priest class, melee class, archer class, summoner class, etc. which all have very fundamental differences in how you play the game. In ME, you shoot shoot shoot, special ability, shoot shoot, special ability, shoot shoot.... It is not a fundamental change in how you approach the battle between the different classes.