Armor works. Arrows and archers in the sources describing medieval battles are little more than an annoyance to armored men. Here's a clip of Egyptian lamellar armor withstanding a seventy-five pound pull bow and at ten yards. That's little links of lacquered leather reflecting an arrow, just to be clear. There are a number of videos on youtube of arrows (bodkins, usually) piercing lightly woven mail, so not all armor worked all the time to be sure. There are also some interesting videos of mail being driven into the target by the tip of a sword and never bursting the links, which means it didn't have to be repaired after every single battle (a common question I've had from my players). On that, here is a bodkin arrow failing to penetrate all the way through some mail.
Of course, that doesn't include the crossbow or the Roman scorpion. These weapons have enough power to drive straight through mail and even segmentatum. In essence, armor is remarkably effective, no matter what you see on the internet. Not sure how that could be modeled properly in a game—there'd be a lot of fatigue and wearing down and less SHEARING OF LIMBS and such.
There are a few rules that I've been thinking of to model ablation in the 2e system. Every time I toss it over, however, I decide against posting anything about it. This has gone on for two years, so I figured I might as well get these thoughts out there since I'm not doing much good chewing them over.
Armor would have an ablation value. It would stack with 1 point of the value of armor beneath it and have different ablation values against different attack types. What the hell am I saying? It'll be easier to see.
Armor type -- S/B/P/Lightning/Fire
Gambeson -- 1/2/1/3/0
Mail -- 3/1/2/-2/-1
This ablation would work against every time damage was dealt. Thus, a man in a mail shirt with a gambeson would have a 3 ablation against a dagger.
This setup suffers from a very long and exhausting combat sequence where weapons deal no damage for rounds and rounds, even in the hands of very skilled combatants.
Another version of this system might use a die.
Gambeson -- 1d2/1d3/1d2
Mail -- 1d4/1d2/1d3
For example, allowing a lower level of armor to add +1. Thus, against slashing mail would absorb 1d4+1 damage. This leaves a range of 0-3 damage an average longsword (arming blade) could do. Critical hits might bypass the ablation? I'm not sure.
These are some ideas that clearly need working out. Hârn and Aftermath! both have much more complicated ablating armor systems that I suppose I need to watch in practice much more before I attempt to reform this clearly broken system.