As I recall, the downside of queueing up a ton of attacks is supposed to be that it leaves you increasingly open to reaction-moments for those you are attacking to respond. If that's the case then that's a pretty good estimation of the reason it's stupid to try simultaneous kick/punch/stab maneuvers in real life - doing so is complicated and harder to pull off.
Sure, but that aspect of having it be complicated and harder to pull off will have to be put in somehow. And kicking with both feet, for example, should be trickier than stabbing with two daggers at a time or some such.
Well, what I'm worried about is that the penalties won't really be large enough to reflect reality.
It's like the modern thing where people try to make some archers look "badass" by making them fire more than one arrow from a bowstring at once - it's just incredibly stupid, since there's a finite amount of force the bowstring can impart, and you're dividing it between both arrows. (Meaning, you're firing two arrows that will have less than half the actual force behind them, be far less accurate, and likely do no damage even if they hit.)
Trying to kick with both legs isn't just stupid because you'll fall on your ass, it's stupid because you won't be able to get any power behind your kicks, anyway, without having something to press off of.
Windmill-swinging dual-weapons is likewise stupid because without balance, you can't throw your body weight behind the attack, and without that weight, you have no momentum to lend the attack enough power to pierce a target.
In fact, to a degree, the game already kind of models this well - it's not getting a bunch of attacks in quickly that matters, it's getting that one lethal attack in. A two-handed weapon that cleaves a limb or a spear thrust that hits a vital organ is worth more than even hundreds of bruises.
I'm just hoping that this update helps move DF combat more towards a model like what you see in something like Mount and Blade, where it's a matter of guarding and feinting and blocking and shoving and positioning and trying to wait for the moment where you can get in that strike that knocks them off-balance, and then going for a brutal finisher, rather than a game where you just windmill your swords at someone and hope that sheer volume of strikes leads to a lucky crit or more aggregate damage.
I'd rather DF combat be like a puzzle game where you try to force the opponent into an error than this kind of utter crapshoot where you just try to roll more dice than the opponent to get lucky first.