I think you're starting to run up against a fundamental limitation of RPGs, to wit, the two competing forces of realism and playability. Yes, realism is a good think, in general. But if one goes too far towards realism, things start to suck for two reasons:
1) The system becomes massively unwieldly. The ideal system interferes with the story/action/whatever as little as possible. This is the motivation for diceless RPGs... don't wreck the mood by stopping to role dice every time someone tries something, and just make up something appropriate. And its a decent idea, just hard to deal with for the GM, as coming up with realistic results for fanstastical characters on the fly is, to say the least, challenging.
2) The system becomes too real and ceases to be fun. Let me give you an example. When I was about 10 my brother brought home this new game system he had found (Runequest, if you care), and we decided to try it. It payed exception attention to detail... character creation took hours... characters had fully fleshed-out skills, abilities, and equipment consistant with the surrounding world. Whereupon we (the NPC and my character) walked out of town, ran across a monster, and attempted to slay it.
At that point I needed to create a new character, as my first one had gotten himself impaled on a spear and found himself rather dead.
So I did. This time optomizing for combat ability. And in all fairness, that character faired slightly better. In his first combat he managed to slay the orc (yes, singular) and survive... though it did cost him the use of one arm for the rest of his life, whereupon my brother and I concluded the system was dumb and went back to AD&D.
My point? Realistically, the average starting adventurer has an exceptionally short lifespan. Realistically, any combat that is dangerous enough to be interesting will wind up crippling or killing much of the party. Realistically, after the first time you get bitten by a dragon, hit with an axe, or shot with a shotgun, you should die or, at the bare minimum, be out of the fight. But that makes fights either exceptionally fatal (everone hits a lot and people drop like flies, as Runequest above) or extremely boring (no good examples of this, though Star Wars first edition comes close... to kill a typical stormtrooper you need to shoot him about 4 times, you only get one shot per round, and only hit about a third of the time. It takes an hour to roll out a fight between a party of three and five stormtroopers. And the party lives... though most probably need medical attention...) as hit probabilities are minute.
Thus, the ideal RolePlayingSystem, in my book, is fairly realistic but also ignores the more cumbersome details in favor of 1) what is easy/fast to adjucate and 2) what makes for a good story. Its fun to slay the dragon. No one wants to hear about how the party needed to sew themselves up afterwards.
I don't think such a system exists yet. There are a few that are pretty good, at least over some level range, but all systems break to various extents at some point and tend to fail in one of the above ways anyway. But I think it would be fun to try to design a system that didn't break down like this. But that's a bigger project than I really feel like messing with at the moment. -- SteveHaas