I like martial arts and combat sports, and have practiced a few of them. I enjoy fighting. I enjoy watching it too. I always look forward to the Olympics, as it gives me the chance to sit on the sofa and binge-watch top level judo over a period of days, as though stuffing massive dogi-wearing chocolate eclairs into my face like some sort of combat-sports-watching beached whale.
I also like wargames. Pretty much the only computer games I play are ones that involve military strategy and huge numbers of slain pixel soldiers set to a backdrop of Barber's Adagio for Strings.
What combat sports and wargames have in common is that they're not very realistic. Let me explain. I watch a lot of youtube videos about martial arts. One thing you'll have noticed if you do the same, is that youtube is absolutely awash with aggressive commentators explaining why martial art x or y "sucks", typically in comparison to the muay thai/Brazilian jiu-jitsu combination practiced by most cookie-cutter modern MMA fighters. These are people who have fallen for the clever marketing of the Gracie family and the later promoters of the UFC, K-1 and similar, which makes a great show of how "realistic" their product is in comparison to, say, judo or tae kwon doe. I will restrain myself from ranting about the problems with this attitude and the sociology of it - suffice to say, teenage boys seem to strongly believe that some combat sports are more "realistic" than others.
But no combat sport is really very "realistic". Striking sports - whether karate, boxing, tae kwon doe, or whatever - almost always insist on the use of gloves (as much to protect the fist as the face). The rare ones that don't (kyokushinkai karate is the only one I can think of) prohibit punches to the head. Grappling sports, like judo, Brazilian jiu-jitsu or greco-roman wrestling, typically prohibit strikes and various techniques which an opponent would almost certainly use in a real life-or-death fight (like eye gouges, groin kicks, etc.). MMA may look more realistic than judo, but that's just a clever illusion - a UFC fight is as unrepresentative of the conditions of a street fight as is a bout of Olympic tae kwon doe.
Similarly some wargames try to produce a veneer of realism - I'm thinking of things like Advanced Squad Leader or the modern updates of computer games like Steel Panthers (which is still modded to this day). Don't get me wrong - I yield to no man in my love for that sort of thing - but again, one has to be very careful about claims of representing reality. Those games may be detailed and complicated, but the conditions that they represent (rough parity of forces or ways of balancing delay vs attack, etc.; emphasis on tactics and lack of emphasis on logistics; failure to replicate individual initiative and cowardice, and so on) are not "real".
The desire to have "realistic" combat, then (one which I feel myself, I think it is important to confess), is a red herring. What is important, rather, is combat which is interesting and detailed enough to reward a good player. It doesn't matter that judo is not particularly realistic; what matters is that it is a tactical and detailed sport in which the best fighter in the bout typically wins, by making the most of his technique and physical strength. Similarly, it doesn't matter that Steel Panthers: World at War is not really a "real" representation of a World War II battle; what matters is that there is a lot of depth to it - such that the most intelligent and thoughtful player typically wins.
Why am I talking about this? The same is true when it comes to RPGs. Some RPG combat systems appear to be more realistic than others - and many, indeed, make explicit claims in that area (I'm thinking of Cyberpunk 2020 and the more recent Blade of the Iron Throne, as well as Rolemaster and Runequest). But I'm increasingly of the view that is a quixotic goal. The reason why Cyberpunk 2020 or Rolemaster have interesting combat systems is not really because they are "realistic", but rather that they are detailed and complex to a sufficient degree to reward a player's intelligent play. Their choices and ideas and decisions really matter, and matter in ways that are predictable (or retrospectively reasonable).
This is also why D&D, in the hands of a weak or mediocre DM and players, has such a dysfunctional and bland combat system - it is not in itself enough to reward intelligent play. (If anything, it does the opposite - if you have better AC and more hp and do more damage than the opponent then you will win, and the process is effectively mechanical. Just keep rolling the dice until you win.) Of course, in the hands of a decent DM and players, the combat system works well, because it is simple enough to add lots of complexity in the form of movement, improvisation, tool use, good planning and so on. But in the abstract, at first glance, its combat rules are simple and robotic. Their virtue, if they have one, is that they are easy and transparent enough to get out of the way to allow the players and DM room to improvise and put their own detail into what is happening.
What's important in an RPG combat system, then, is not how realistic is but how much it rewards player skill. Does it have the right level of detail and complexity to make player choice and player thought matter?