A few years back (younger and more pretentious), I came up with a technique I call "wolfpack memetics". Since a few people have asked me for more detail, this will tell you what it is and how it might help your designs.
The idea is to include things (usually characters) of a wide variety. Basically, everyone is bound to like somebody, no matter what their preferences are.
Obvious examples can be found in any series which has more than four characters in it. Naruto, for example: I find it to be a worthless anime, but it does have several characters in it I like anyway. Shikamaru is my favorite. If you've seen it, I'm sure you saw some characters that appealed to you. They probably aren't the same ones.
In an interactive medium (games), this can be especially powerful if you let your players choose which characters they want to interact with. Baldur's Gate, Planescape: Torment, and other American RPGs with parties tend to be extremely good at this, with complex NPCs you can choose to ignore or get to know better.
Japanese RPGs tend to be much worse at it, with mandatory character use. Your favorite character may only play a bit role, or you may be forced to take on a character you despise enough to make you instantly quit playing the franchise (coughQuinacough).
On some level, the idea is to create an ecology of characters. No matter what the audience's niche, they'll find something in their food chain to chew on. But you don't want to crash your ecosystem with characters that tip the whole game into unbalance.
I called it "wolfpack" because of the nature of a wolf pack. On a per-wolf basis, a pack of wolves actually brings down less meat than a lone wolf. However, each wolf gets to eat more meat for less effort, because the wolf pack has more efficient hunting habits and can keep scavengers and large predators at bay until the whole pack is done chowing down.
By forming a "wolfpack" of characters, you won't bring in significantly more audience. But you will "eat" the audience more effectively, because you're coming at them from every direction.
Of course, there are problems with this. Your alpha dogs have to be liked by pretty much the whole audience, or the wolfpack won't even be in the right area to go hunting audience. Your lesser dogs can't unbalance the pack, and they can't be so mangy and disease-ridden that the prey smells them and runs away (coughQuinacough).
The fewer "wolves" you have, the more careful you need to be about triangulating them, and positioning them to corral your prey. That's why a series with four or five characters has a strange, frantic feel: the wolves are desperately sprinting into position to cover and chase the audience.
Character interactions seem more normal with eight or nine, because there are enough wolves to cover the terrain and trade off chasing duties.
Anyhow, if I developed this theory today, I'd probably call it something slightly less pretentious. But it's an old theory.
Actually, it's so old that it's been completely replaced and is now a corollary of another theory. But that theory takes a long time to explain...