In RPGs (and other genres too) there are two types of heroes: the silent type and Story Type.
Mind you these are only MY terms that I will use throughout this article.
Silence is Golden
The silent hero seems to always silently concede to whatever the story says or supposedly respond to any question addressed to him/her. Link and Mario are some of the more obvious silent heroes. Although Mario and Link make "noises", they do not respond verbally to any dialog aimed at them. (In recent 3D games they have started gesturing). Dialog with NPCs and cutscenes always feel one-sided.
Some of the benefits of using the Silent Hero is that you never put words into the players mouth. This is to say that the player IS the hero. The silent hero does not have a bold personality per se, because that portion is suppose to be filled in by the player. In a yes or no situation, it IS the player saying yes or no. In a way, a silent hero is easier to relate to because his dialog is not showing off any personality.
The disadvantage of course is the one sided conversations which can feel a bit off. It seems as if all the NPCs assumed your response and can talk for centuries while you just listen not saying anything.
These are story characters that a game designer developed for a specific role in the story. The player may or may not relate to that character. It all depends on the personality of the character. Still, it puts the player in the position of playing a hero that is NOT them. If we use language of literature, the player plays from a 3rd person view instead of a 1st person view that a silent hero can allow.
The benefits of the story hero is that NPC conversations are not one sided. Players can grow to like and relate to a well-developed character. The character's growth throughout the game story is visible or more obvious. It also allows for voice acting.
The disadvantages are almost the opposite of what a silent hero provides. It puts words in the player's mouth. The player might feel left out of the game, as if their choices in the game did not matter. There is always a danger of the character estranging the player from the game.
Which is better?
It is up to the game designer, since neither is really better or worse over all. It all fixes on the purpose of the game. Stories can be portrayed through both a silent hero or a story hero. The experience that a player gets is what matters.
Story Heroes are very popular. Like a hero in a book or movie, the player chooses to relate or not based on the character's actions and behavior within the story.
The relation and dialog between the hero and non-player characters (NPCs) is a key element in an RPG game. In the story hero case, the conversation is two-way. The NPC says something and the hero has a predetermine response. Sometimes input from the player can change the flow of conversation using branching dialog.
For the silent hero, the dialog is one sided. It is not a simulated conversation at all really. The NPC will rattle on and on, only pausing every so often for a yes or no response. (Usually the response HAS to be yes to continue with the game.) The NPC will continue to spout dialog to the simple "yes" response as if the hero had agreed to ALL the terms of their quest. The other thing that happens for a silent hero is having a talkative NPC partner. They might do some of your talking for you.
I normally have a preference for a story character. But this is because, as I mentioned before, that I have narrative motives when I play a game. I'm playing for the story. If the characters are obnoxious or a personality I don't like then I usually do put the game down.
I don't mind the silent hero because it has it's benefits.