
Perhaps its a case of too many games having spoiled me with the ability to create my own character and tailor his/her appearance, but I'm finding it harder and harder to get behind a game that doesn't allow me to do so. Instead forcing me to play a stock character.
Even as simple a customization engine as games like Mass Effect have make the game more enjoyable and give a greater sense of self involvement. I know a lot of female gamers are much more inclined to pick up a title that allows them to choose their characters sex.
Theres also cases where a true "create-a-character" engine doesn't exist but instead gamers are allowed to redress existing characters (such as what Capcom does in the Resident Evil series) but if this is done, then there needs to be a large assortment of costumes available (continuing with the Capcom theme, like what was done in Dead Rising). Even this can help appease the need to feel attached to our characters that drive many gamers.
Making different looking characters can also greatly improve the chances that a title will have a strong replay factor as I'm more inclined to sit through the game again if I can place through as a different character the second time. Not to mention, if the game is online or you're over at a friends house its always fun to see what other people have done with their character's appearance.
Afterall, if i'm going to be looking at a game character for 20-30 hours then I at least want them to look the way I want.