I was was watching Deadliest Warrior the other day and saw this episode.
The premise of the battle is one on one combat, which is crazy when you consider that Spartans fought as units and Ninjas preferred to kill by surprise. (not to mention the 1500+ years of history separating the two)
Putting logic aside for a moment, it was an interesting show. Strength vs Stealth, Bronze vs. Steel, Direct vs Devious. They input scads of data and run a simulation 1000 times.
The closest D&D equivalent would likely be a monk or an assassin vs a fighter...
I wasn't too surprised by the outcome but, it was interesting how it played out. The Ninja had a very difficult time getting past primitive Bronze armour even with steel weapons - the shield was key - it stopped almost all of the Ninjas distance attacks as well as foiling many of the other weapons (a katana/ninjato would probably break on the shield). The ninja could hurt but, not really kill the Spartan in a single blow (he would have to whittle him down). By contrast, if the Spartan hits, it's pretty much over.
In the simulation the Spartan won 65% of the time. What I thought was interesting was that most of the Spartan kills came from shield blows and not the Spear or sword. In the testing they were able to generate 45 Gs from a shield blow using the edge of the shield. The bulk of the rest of the kills came from the spear. The Ninja's best weapons in the simulation were the Kusarigama (ball, chain and sickle ) and the sword.
This makes me think that in D&D, the shield and the spear are way understated. A spear should do a helluva lot more damage than a short sword (likely more than a long sword) and a shield should provide massive improvements to frontal armour class as well as being an effective 2nd weapon when trained to use it as such.