Spoilers beware! This article spoils RuneScape. If you haven't played the recent quests or don't want them spoiled, do them before reading this. You won’t regret it.
The choice mechanic is a popular trend in Role-Playing Games these days, with games like Fable and Mass Effect (And I name these because I am addicted to them) letting the player choose how their nameless hero acts or how Shepard solves problems. Games have always been interactive, but until recently the stories weren't. You were a player in someone else's story, going through the motions that they set for you. Now, you are still playing someone else's story, but you choose how to go about it.
The recent Void trilogy brought this to Runescape's quests. Until recently, your actions in a quest had no bearing on the outcome and rewards. Choices were purely cosmetic, you could say something different and get a different response, and that let you role play the character you wanted.
In Temple of Ikov, for example, you could choose to either give the Staff of Armadyl to Lucien or protect it from him, but when While Guthix Sleeps, its sequel, was released, players who supported the Armadyl guardians received a letter telling them that the Staff that they protected was stolen anyway. Players who turned the staff to Lucien were even allowed to continue working with the guardians against the being that they previously worked for, which would be wildly out of character in any other medium.
In Tower of Life, you could influence the Homunculus towards magic or logic, in what may be one of the first examples of character development for an NPC. Unfortunately, after doing so it tells you that your actions again did not matter, and either way it has become balanced between the two.
Rewards are worse about this. The main choice was what skill you wanted to spend your experience lamp or post-quest training on, though Roving Elves rewards you with a crystal item based on preference. These rewards were never tied to your choices during the quest.
The Void trilogy changed all of this. Throughout three quests, you were given a set of choices, and part of the reward was an Elite void knight plate based on your responses.
Only a few of the choices affected gameplay directly, so the player would be encouraged to make theirs based on a personal response to the story. Should you free the pest, even though it may be dangerous? Should you execute the Black Knight captain? Will you save Korasi or Jessika? That is up to you, and for the first time, Jagex has differentiated between the merciful and ruthless heroes in gameplay.
The choices are still fairly superficial. The only difference between the three pieces of armor is the color, and there is currently no greater gameplay consequence for your choice. This is not a bad thing, because if the rewards were dramatically different based on your choices, players would specifically choose the path that gives them the reward they want, and a game mechanic that could add depth to the story instead becomes another mechanic for a pragmatic player to abuse. After all, why roleplay a merciful character in the quest when your lack of remorse could get you a much more powerful item?
This, I think, is the right way to incorporate choice into Runescape. Players are encouraged to make the choices they feel are right rather than the choices that will benefit them the most in the long run. If Jagex continues this trend, players will have many more story options, meaning more integration into the plot, and more investment in the characters. And some varying rewards would be nice too. It's pretty boring to see every high level player in identical gear, isn't it?