Well I think character design can be quite important, but it's not only the design of the character it's the qualities and personality that the character portrays. When I think back to my favourite characters from TV shows, movies, game characters, thats is one of the main attraction for me, because I like something better where the character can relate to me, on who I am or like to shape to be. Such as many people in real life, characters from such genres can also be massive inspiring idols. Which can give you a sense of structure, morals, educations, personality and so on. You get a sense of connection that really can't be explained and to what a 'fictional character'? Yet in some way it feels so real?
I believe without these such fictional characters the world be a wrong and boring place to be in, because it's a good way to see many different personality traits expressed in different formats, from books to film to games and obviously this then leads to visual design. There is also a lot to consider if it's in the entertainment industry, because the right voice acting and personality to be true to such character say based from a book, can be a tough thing to get right.
Many characters from the Marvel and DC comics, are pretty much a bible in a way, it can teach people a lot of things;
Superman for instant is a pure-hearted being that shows to people empathy and passion, also how the right and moral thing to do. Which by this can inspire people and some one to look up to.
and people also take liking to villains, but in reality, most people wouldn't do so, but it's a strange one that people take a liking to villains, is it the general style of how they portray or the cleverness or certain things again gives the peers emotional and mental attachment and sympathize with.
For example the Joker, people find him fascinating, bad ass, mysterious and so on. Yet his down right a murderous, psycho, reptile traits of a person which 9/10 people would like to see him lock up and so on, if he was real. Though it's strange people get a different sense and so a 'bad person' because an idol as well to many people.
As in most things you can have 'side characters' but in games these can be classed as NPC ( none-playable-character) which interact with the main hero/villain that help fill with the story etc.
Alot of games these days focus a lot of development and interaction with an avatar that you personally customize and create yourself and follow a story that been set, which a nice addition of features that you create and personalize on your avatar you created.
Saint Row - The Third
It's pretty awesome that you can have options to create your character male or female, many features and clothing and option to customize to a good potential or even create other existing characters with the tools there. Then by unlocking new stuff, this can also add more dramtic style and feeling to the game, you can get very trapped in customizing your character to look like you or something ' cool ' which you can get very picky in decided what jeans to wear with this jacket. This can attract the consumer because it's always fun to play a game that resembles a essance of you.
However a game which is just like Saint Row in terms of gameplay and genre;
Grand Theft Auto 4
That you play as the main character called Niko Bellic, a thirty year old veteran of an unnamed war in Eastern Europe and so on. So already we have got a plot and ethnic background to go from, that his main location is the west to Liberty City to pursue the American Dream.
So even knowing that amount you can expand from this and his design of the character gives you a sense of a military kind of guy and foreign with a troublesome past, with only knowing anything but the visuals. I believe it can be more rewarding depends on the circumstance, that can give you like or dislike getting to know a character as you unravel the story in which the universe the character is placed in. To just create your own avatar and play though a linear storyline can sometimes lose it's seriousness but for such genres like this and having an option of creating a character of choice with some identification and story, can be a good thing, but having a main character which you know so little and want to know more, you feel that the adventure of finding out make it a lot better playthrough.
In first person games, sometimes the main character isn't as memorable that what you play and see in a 3rd person view. Though such First person shooters games where your only visual is your hand and the gun of your character, that the main attraction is the NPC's which is the attraction you play a long side with and through the story, which your character is only a simple vehicle with not much personality, but in this way you feel still engaged and a good sense of adventure because there are other characters of interest which seems more important and your satisfied in that.