Maybe I can't write like Shakespeare, but he ripped off most of his best ideas, and I can certainly follow in those footsteps.
To be honest, I mostly steal concepts, ideas, character archetypes, and themes. I recombine them, recycle them, and re-use them. I'm an ecologically-aware writer, if there's ever a world-wide idea shortage, I will be on the forefront of the idea recycling movement!
You only have so much time to tell a story and you have to share it with the players and what they want to do. If I need to spend a lot of time establishing a particular character, or society, or bit of technology, that's basically just me sitting at one end of the table narrating to my players. It's not really interactive and unless I'm a really good storyteller, it's kind of boring. Heck, sometimes even I get bored of doing all the talking. Every word I can avoid saying is another word my players can jam in edgewise. Believe me that's a good thing.
Ripping off somebody else's idea - especially a well-known idea that is shared by most, if not all of my players - saves a lot of time. For example, if I base a society on Imperial Rome and drop a few not-so-subtle hints about it, all of my players have a big leg up on the story I'm telling and they can then cooperate by contributing their own bits if they choose to. If I want to introduce a character with crazy-advanced technology and I have them whip out what is obviously a sonic screwdriver, the players are likely to recognize it, even if their characters don't. It's a short cut and it puts everyone on more or less the same page. Now I can move the story along and give my players some well-deserved spotlight time.
This is even more useful in a one-shot game. When I'm writing a character sheet for a 4 hour live action game, I like to keep it under six pages, including abilities and contact list (the ever-popular 'Who You Knows'). That doesn't leave an awful lot of room. If I could make the sheets shorter, I would. Most people won't memorize much more than two pages, so every page I go longer is that many more times a player needs to whip out his character sheet and bring the game to a screeching halt while they 'search their memories.' I like to keep things moving and minimize character sheet checking, so I keep the sheets short.
The best method I've found for having well-rounded and fleshed-out characters that can be written in under six pages is
Characters aren't and shouldn't be static things. Even a concept that began as a point-for-point
Taking other people's characters and putting them into new and different situations is nothing new, fan fiction has been doing it for decades, taking other people's ideas and expanding on them or re-combining them in new and different ways isn't new either, it's called 'genre.' But using it as a short cut or place holder for character development is a powerful application for both players and game masters of tabletop and live action games.
There are other ways to go, of course. I've gotten more than my fair share of twenty page character sheets, I've seen a lot of bold and unique characters, in fact some of the best players, writers, and game masters insist on creating entirely new and original characters every time. Some situations call for originality and others call for a reference. Keep a large toolbox and