There has never been a realistic pen and paper system.
What people mistake for realism is process simulation where you go through the mental steps that naturally arise when you imagine combat. But this isn't realism, just something that gives a semi-skeptical person plausible suspension of disbelief.
Take the common claim that armor as DR is "more realistic" and D&D's abstraction as making you harder to hit. It's sounds sort of reasonable except that isn't really how armor typically works in a melee combat situation. If you have two heavily armored warriors, neither is either trying to or likely able to hit the other hard enough to break through the armor. That's not how armored combat generally works. Rather, the armor generally fully protects parts of the body while not fully protecting others, so that combat comes to be about trying to score a hit on the much smaller vulnerable target, often after obtaining some sort of advantage (drawing a shield away, knocking them prone, drawing their guard to one point and then switching to attack another). The simple simulation of either armor as DR or armor making you harder to hit are both equally unrealistic or else equally realistic for a narrow range of armors and types of attacks or skill ranges of the participants.
Runemaster is no more or less realistic than D&D, it just feels a bit less abstract, and the series of steps matches our expectations about what the steps are a bit better.
The ur-example of this for me is Drawf Fortress, which takes this intuitive process simulation to the extent of modeling iron, padding, skin, flesh, and bone in various thicknesses in an attempt to realistically model attacks. Tons and tons of process simulation goes into it, and I think if anything it produces narrations of combat that are the least realistic looking things I've ever seen. It doesn't successfully emulate what is implied by HEMA, SCA or any other mock combat art. It frequently becomes pretty ridiculous, with fights devolving down to extended attempts of the two exhausted combatants to wrench the others pinky finger off because well, that's the thin point that's most easily damaged and the system doesn't really handle gaps in the armor or deliberate attempts to strip off the armor or ton of other possibilities that would come up in a similar real situation.
Pheonix Command for all of its process simulation is not more realistic than D&D.
Now, process simulation does achieve interesting things but those things aren't realism. It does achieve what I refer to as "cinematic" play because it does produce a concrete transcript of events that help all participants imagine the same outcome. It can encourage less abstract combat propositions, by encouraging a player to describe their stance, attitude, and goal more concretely. But it's not inherently a better simulation for being more detailed or inherently producing more realistic results, because so much is still left out and in most cases numbers are just picked out of the air because they fit or they are believable to the designer.