Some random thoughts I had this week.
1. Knives (and fists)
Have you ever held, or even seen, a fighting knife?
Goggle it if you want. This thing is REALLY dangerous. I'm pretty sure any random person could stab a trained fighter to death with ease.
In fact, I have recently heard a jiu-jitsu champion say exactly that.
AND Eddard Stark is held by a knife to the throat in A Game of Thrones.
So it's both true in real life and in TV.
No 1d4s, hit points or saving throws.
One good stab and you might be dead before you can do anything about it.
No so much.
Even professional fighters might have a hard time knocking someone with a punch.
But sometimes a single hit is enough.
On the other hand...
Seeing someone in armor really makes you think combat is survivable.
Again, not only in TV, but even in youtube channels that study the issue seriously.
Even in medieval manuals of arms, a longsword (1d8? 1d10) would require special technique to wound someone in plate armor.
Killing an ironclad warrior would usually require some grappling and a long dagger.
Or just a mace.
3. A solution
The easiest way to combine both in a D&D context would be having some small damage that would get MULTIPLIED against little or no armor.
Say, hit 10 points above AC means "critical damage".
12 points: double damage.
13 points: triple damage.
14 points: quadruple damage.
If your armor is not that great, you're always one good hit always from being killed.
Blunt weapons would deal more damage, probably, but the "criticals" might be less dramatic.
Maybe slashing and piercing damaging have different "crit" number.
So, a dagger would be d4 (crit d8), and a longsword d8 (crit d10), for example, and a mace simply d6.
This manages to both make knives very deadly against opponents with no armor WITHOUT requiring repeated rolls, while also making decent armor very useful against blades etc (but not impervious).
Of course, the chances of rolling AC+10 are not usually that great.
A better solution - for other RPGs - would be using a d100.
Say your "dagger" skill is 70, and you hit 70% of the time.
Treat "doubles" as crits. So, 11, 22, 33, 44, 55 and 66 are criticals.
And you get to double (22), triple (33), quadruple (44), etc., your damage.
This stuff happens very often - about 10% of the time you hit.
A skilled knight could kill a dragon with one blow.
Armor, of course, would REDUCE incoming damage... up to a point.
So, instead of taking, say, 10 points of damage, the wearer would take 3... Not that much, EVEN if you multiply by four or five.
Starting HP would be at least 40...
Of all the systems I have played, GURPS comes closest to this.
Unfortunately it has too much die rolling and a critical hit table in which "nothing happens" is the most likely result.
But I reckon a simple "critical hit" table would take care of most of this stuff, even in D&D.
I've been there already... Oh well.