I don't know what Excidium's problem with KCD's combat is, but the arguments are weak. In any kind of professional/martial fighting, technique >>>>>> anything else. Only when the technique is roughly equal between the opponents do factors like speed, endurance, strength, size, etc come into play. For a good example of that, see the early days of Mixed Martial Arts, when Royce Gracie (a very mediocre relatively unathletic, small sized dude) dominated muscle bound behemoths with only superior technique. Now that everyone learns Brasilian Jui-Jitsu in MMA, things like strength and conditioning matter, because the technique is much more even across the sport.
Also, HEMA is pretty accurate stuff. Obviously it's not 100% accurate, as they use dull swords for safety and stuff like that, but it's as close as you can get to historical fighting short of killing each other. I watched a lot of their videos online, and if anything, those guys very often point out the myths and inaccuracies from ancient manuscripts and inexperienced practioners, because once you are out there practicing those moves and techniques in real life, it very quickly becomes obvious what works and what's bullshit. So if these guys like KCD's combat, I'd say it's probably really close to the real thing, within video game limitations.
Disclaimer: I haven't tried it myself yet, so for all I know, maybe I will hate it too once I try it. But from the videos, looks pretty neat, with everyone changing stances and guards, using different attacks and counter-attacks. That's way more complex than the typical button mashing crap in RPGs, so I don't see that as a bad thing in any way.