BRP, RQ and similar systems work well with the "I hit you and you hit me and we dodge about a bit" way of fighting. I.e. the kind of thing that I would do if I wanted to work a combat out.
It doesn't handle all the intricacies of martial arts.
That's why I always say that any rule in roleplaying games will satisfy most people, but experts will say that it is rubbish.
Look at all the debate over unarmed combat - Experts in judo, ju-jitsu and aikido don;t like the throwing/grappling rules as they are too limited and don't reflect real life. Experts in taekwondo, karate and kung fu don't like the moving/blocking/parrying/flurry rules as they don;t reflect real life. Experts in fencing or the various martial arts that use weapons don't like the combat rules for the exact same reasons.
It all depends on what level you like. RQ/BRP still reflects what I see in my head when imagining combat, even with the little bit of martial arts that I did when I was younger. For me, that is fine. For experts, it will never be fine.
A roleplaying system that handles all the intricacies of fencing, kendo, aikido swordplay, kung fu weaponplay and all the other martial art forms out there would be far too complicated for my tastes and, I think, would not work particularly well.