Grimrock

Those who are saying that realism is unnecessary in a fantasy game — are severely confused.

There are two kinds of realism. One is inversely related to the flight of fancy. Let's call it "literal realism." The goal of literal realism is to accurately describe the world as it is. No imaginary empires, no non-human races, no mountains with dungeons, no teleporters, et cetera. In other words no fiction in any way, shape or form.

We all know, however, that there is such a thing as suspension of disbelief. We temporarily accept the rules of the narrative, and enjoy the story. Yes, we know that minotaurs do not exist, but we pretend that they do. Interestingly enough, it doesn't take much effort for us to allow tons of fantasy elements and still perceive the story being told as "realistic." To this end, literal realism is unnecessary.

There is, however, another kind of realism. It is related to the fundamentals of the physical world and human cognitive ability. We can call this one the "pedantic realism." It is quite simple really, because it deals with things such as gravity, logic, prime emotions and so on. Violating pedantic realism will kill any story at once. We are simply unable to adequately perceive and process outside of its set of restrictions.

Let's talk about strength and dexterity now.

If someone has incredibly large and dense muscles, they are very strong. If they hit you with a stick, you are going down. If, however, they are too slow, and cannot actually land a hit, what good is their strength in a fight? This is where dexterity comes in. In real life a fighter can't just be strong, they also have to be fast.

Now, if someone in incredibly nimble and flexible, they are very dexterous. They can dance, and do cool things. Will that do them any good if they wanted to shoot a bow? Sure, they might assume the perfect posture, and aim very precisely, but if they don't have the strength to pull that 120 lb. string, all that dexterity is absolutely useless. Same is for throwing weapons. If you are weal, that knife you throw is going to fall right in front of you and not hurt anyone.

See where I am going with this? Such basic things DO need to be realistic. Otherwise the suspension of disbelief is likely to break. And nobody wants that.

See also "verisimilitude". Also the famous essay "Crimes against mimesis" (can't find a link now, someone apparently archived it on geocities), not to be confused with the hilarious IF game "sins against mimesis" based on it.

Alaric,

(Not quoting for brevity). The only thing that fails your test is that dex does not impact accuracy for ranged weapons. This is merely a design choice for simplicity though. The game is balanced accordingly, specifically the amount of ammunition available and the damage done.

If ranged weapons were to miss based on dex, they would have to increase the ammo available and boost damage from the weapons as well. You'd also spend more time trying to recover your ammo, especially shots that miss.

There's a significant trade off here just accommodate that "realism" of dexterity affecting ranged hit chance. I suspect this decision had a lot more to do with the game play aspects of ammo management than any combat statistic balancing issues. Consider that "picking up all that ammo" was one of the most universal complaints from DM, it was a logical continuation from the "auto-pickup" idea.

Of course. A game (any game) is a simplified set of rules. For example the heroes of Grimrock neither drink nor ever go to the bathroom. These simplifications fall under literal realism for the most part, so we easily forgive them. Moreover I imagine it would be next to impossible to design a game that is absolutely realistic in every aspect, so shortcuts have do be made for the sake of gameplay and relative simplicity. A game has to be fun after all.

What I'm saying is that dexterity is implemented very reasonably, and that those who claim that all realism is unnecessary in a game, are plain wrong.

Alaric you couldn't have said it better, of course I already saw the difference, but now it's simply written down in good english and everybody can understand, I don't like when people, to sustain their point, make a lot of confusion between the different kind of realism you've spoken about.
In my opinion it's not a matter of what system people are used to, (D&D etc.) but rather what is intuitive and what isn't, for example: nobody would say you need strenght to get more damage out of a crossbow, because it's a mechanical process. It's unintuitive that missile weapons never miss regardless of what attributes your character has, because in the real world (and I hope people now know in what sense I am saying "real") there are a lot of things you get to take into account, dexterity represents accuracy that's ok, it's intuitive that better coordination results in less missed hits.
What I find unintuitive is that: dexterity should be a primary attribute for ranged characters and is not, because it represents accuracy and coordination. Simple as that. Instead strenght comes into play and it seems rather weird to me and unexplicable.

Edit: I also agree with jfunk, this choice about dexterity can't be explained with anything but simplicity, it saves up a lot of balance, as he already has said, you can't try to defend it with an intuitive argument, because it's not. Developers chose to do it this way because it kept things simple as they should be, even if it meant to go against intuition.