The "called shot" problem

One of the things that D&D tries very hard to do is make combat both interesting and accurate. So if you wanted to strike a person's hand or wrist or even their helmet specifically, you should be able to, right? You might even grab the rules sheet and call this "a ranged disarm" -- as this forum suggests -- which means a -4 penalty and allow a ranged disarm attempt. Or what if you want to hit that little green gem in the monster's forehead?

Well, issues with this problem are several and well-noted.

Suggestions on this thread included a "called critical" where the attempt is to make a "critical strike" (how D&D handles damage to weak areas). The attack would be aimed at a particular portion of the body. If its critical, they hit that part.

One suggestion was "unless you're using another option, your character is already trying to do that and on a crit he succeeds."

Related:

• A variation on "power attack" using dexterity.
• Free vs. swift actions (also)
  

Keeping track of the rules

I'm posting my rules Cheat Sheet, which helps me keep track of how things work. Will hopefully add to it as time goes by with my own custom stuff.

Attributes

One of my players suggested that attributes didn't make any sense. I remembered one of the tricks for using 3 six-sided die to determine stuff like strength, dexterity, intelligence ...

The idea is to answer the question: could an average human do ___ action? All they have to do is roll their attribute or below. Someone with score 10 (an average person) has a 50/50 chance while a person with a score 20 has a 100% chance. As much sense as that makes, that doesn't come up in D&D.

So I guess I'm not really sure why that system is still used.