Kamikaze Midget had a great point back there about The Fast and the Furious and Warwick Davis. D&D isn't about realism, it's about genre consistency.
In D&D's case, the rules are built around the genre of pulpy cinematic fantasy. The further you stray from that, the less well-suited the rules get.
Change "pulpy" to "historically accurate", and you can still play, but the rules fit less well. Weapons are wrong, the economy doesn't make sense, etc.
Change "cinematic" to "gritty", and you can still play, but the rules fit less well. Characters are way too resilient, martial characters can do all these tricks that "real" fighters can't do, etc.
Change "fantasy" to "science fiction", and... you can probably still play just fine, as long as you reflavor everything properly so that you're playing cinematic, pulpy science fiction.
After all, 4e evolved from Star Wars Saga, so there you go. But 4e would be a bad fit for a game set in (the new) Batttlestar Galactica universe.
In D&D's case, the rules are built around the genre of pulpy cinematic fantasy. The further you stray from that, the less well-suited the rules get.
Change "pulpy" to "historically accurate", and you can still play, but the rules fit less well. Weapons are wrong, the economy doesn't make sense, etc.
Change "cinematic" to "gritty", and you can still play, but the rules fit less well. Characters are way too resilient, martial characters can do all these tricks that "real" fighters can't do, etc.
Change "fantasy" to "science fiction", and... you can probably still play just fine, as long as you reflavor everything properly so that you're playing cinematic, pulpy science fiction.
