I'm lurking around again so I thought I'd reply to the original question in a manner that isn't 'see the sticky'.
I noticed that STS3388 has a Blogspot account where they mention putting cartoon characters into their Sim games "see how they would live out", but there is a self-sim with a short biography and the beginnings of a Sim family story. So I'm going to guess that a few of her characters are thought out, but the rest are placed in the game for the reason of placing them in the game. If this is the case, I can understand how that would get boring very fast.
Using this information, my questions are: why/how did these cartoon characters end up in this neighborhood? Or, for that matter, why/how do any characters end up in a given neighborhood? Also, how are the households constructed, are the heroes and villains in separate households or the same household? Do the heroes team up against the common villains or are they mixed together so the "good" character from TV show A becomes friends with the "bad" character from TV show B?
These are just ideas if the situation is 'placing characters in a Sims game to see what happens'.