Role Playing Game idea

A role-playing video game (commonly referred to as simply a role-playing game or an RPG as well as a computer role-playing game or a CRPG) is a video game genre where the player controls the actions of a character (and/or several party members) immersed in some well-defined world. Many role-playing video games have origins in tabletop role-playing games(including Dungeons & Dragons) and use much of the same terminology, settings and game mechanics. Other major similarities with pen-and-paper games include developed story-telling and narrative elements, player character development, complexity, as well as replay value and immersion. The electronic medium removes the necessity for a gamemaster and increases combat resolution speed. RPGs have evolved from simple text-based console-window games into visually rich 3D experiences.

But the interesting part is that, we can create new experiences in what is now the traditional western RPG or Japanese RPG genre, with seemingly small changes and minor tweaking. For example we can create an rpg where people have the incentive to complete every part of the game. The game should have multiple endings, and have factions. It should have complexities like befriending one faction means, becoming an enemy to another another. But you can break away from your own faction or fool the another one as a spy, or become a double agent to experience content from mutiple factions in a single playthrough.

Your moral affinity is assigned based on your actions. So you can become good even after you become evil, its not strictly defined by the choices you make and content is avaulable to you on the basis of you being good or evil.

This with different endings in an massively multiplayer online game setup would also be good. The experience will be defined by the choices you make and different content is available to you on the basis of you being good or evil. You will be able to experience a huge portion of the content available to you in one go. Feature of switching factions will itself lead to interesting events, comparable to side quests, but you will bable to completely control the outcome. 

Since everything is action driven, and past actions can influence things like how much each faction likes you, you will be able to experience a huge portion of the content, but still not be totally sure of the order in which things occur or the ending, you will be able shown, once you reach the end of the game.