That was me, my name on that forum is Slide.
But yeah, in VF basically footstance can determine how combos worked because it's based on hitboxes, some characters would have a different combo entirely based on footstance in reference to their opponent. Some combos even having significant difference in damage. Also footstance could determine secret whiffing of moves, even some unguardables!
Based on the idea of hitboxes, footstance in MK could have some interesting results with whiffing of moves too, but who knows.
EDIT: I was hoping, and still am, that it will make a significant difference for MK. Even if it's patched in an update. Open and closed footstance, is a great feature to a fighting game, and it helps remove autopilot.
Slide? The other R.Mika player? heh, cool.
I was wondering if stance changes did anything in the game since day 1 myself and I've been trying to research if they do, but my thinking led me too to consider that hitboxes had something to do with it. After some research tonight, I believe I have found some useful information, but one that was inconclusive about stance changes. Nevertheless what I found was pretty interesting. Unfortunately I can't capture video and upload it, but I'll try to describe what it was.
I went into training mode with Jade and found some interesting things. Jade's neutral 4 (or bk as we call it here) moves her forward, so I though, I could just hit 4 and see how many whiffs it would take to hit my opponent (in this case Sektor) and then change stances and try it again and see if it was different. Well, it was. But then after doing it again and again, I found that how many 4's it took to hit Sektor was different everytime no matter what stance she was in. In other words, even in the same stance, the results were different on repeated attempts. What this led me to believe is that the character's neutral "swaying" actually can cause a whiff when no directions are being pressed, because their hitboxes are moving, just a tiny bit. What I'm not sure of, is whether it's the hitboxes of the one getting hit, or the one doing the hitting that matter, or both, but below I'll actually describe what I did so you can see how I came to this conclusion.
Straight out the gate it takes 3 bk's to connect. But after that the pushback and recovery makes it take either 4 or 5 more before you hit Sektor again. The thing is, it's not predictable whether it will take 4 or 5. For the record, going into training mode without hitting a direction, you can hit Sektor 11 times before he's in the corner, and will just get hit every time.
So the first time I did it this is what it looked like (wit the number being the hit that actually landed):
3,5,4,5,5,4,5,4,5,5,4,corner.
The second time, in the same stance (default stance,) this is what it looked like:
3,4,5,5,4,5,4,5,4,5,4,corner.
I needed to figure this out so I got an idea, I hooked up my SF4:TE stick and turned turbo on on the "4" button, this way I could just hold the button down and the move would come out as fast as possible, lo and behold, doing this yielded the same results every time. That pattern was as follows:
3,5,4,5,4,5,5,4,5,4,4,corner.
Then I switched stances and tried it...got different results, but it wasn't uniform different results, it was just different every time. So the conclusion that I came to was that it wasn't the stance that was causing it, it was the point in the animation that my character was in when I started the attack, or the point in my opponents animation when they got hit, and since when you hit select to restart the match, you start in the same stance, I had to hit stance change which could, ever so slightly, throw off the timing, so that even on turbo, I got different results, because I started holding down the button during a different frame.
My logic behind this is that it stands to reason that pushback on hit (or block for that matter) would be the same every time right? If I hit someone with a certain move, and it connects, they should always get pushed back the same distance (unless they're in the corner.) Well something in Mortal Kombat makes this not true. But it looks like stances aren't it. Though it's not out of the question that they could potentially affect this if they reset the neutral "swaying" animation.
I did find something else though, that's very very interesting and could affect this.
Another one of Jade's normals that moves her forward is 2 or bp. I saw this move and thought, well she leans forward a little bit I wonder if it moves her forward, and it does, but it's very, very slight. It takes like 30 or so from the start of training mode to hit your opponent
UNLESS you mash it. No combo Jade has starts with 2,2 so I was just mashing the button rather than wait for the move to recover, guess what, she scoots forward MUCH quicker, it's easily visibly noticeable, and turning on turbo for this button has the same effect. I'm not sure if this was already known, if it was forgive me, but those are two interesting mechanics that I'm not entirely sure are intentional that I've figured out so far. Unfortunatley, none of them point to stance changes, but they both could potentially affect gameplay. So I hope this is helpful.
EDIT: Ok, so more research that backs this up, on second thought it seems like it's a no brainer, but the characters neutral animations do actually make a difference in their hitboxes. I just went into practice mode with Sheeva against Jax and stood where her 2 looked like it wouldn't hit him, but at a point in his animation where he leans forward it does. As far as I can tell her 2 has no pushback on hit and doesn't move her forward...unless again you mash it. It's like kara-cancelling a normal into the same normal, it's weird. I actually think being able to do this was probably intentional, and increases the frames of the attack, kind of like how hitting 1 or 2 in tekken and f 1 and f 2 are the same attack, but the forward versions have longer range and are slower.
So you might say, well, if a character is moving, or blocking, then they'll never be in a "neutral" stance long enough to "lean" forward and get hit by something that would usually whiff. Well, you'd be right, but what this does mean is that there's a few things in training mode that are deceptive, because you might find something that you think is a good setup for a combo at a certain range, that only worked because you hit your non-moving opponent in a particularly "forward" point in his movement where an opponent who moves might not get hit by it, but this is uber situational.
In the Kung Lao example above, it is stance dependent, but also hitbox placement dependent. The low 4 kicks the opponent's leg either into the foreground, or the background, and it's only hittable in one of those states. Also, just natively doing 2,4 Kung Lao changes stances on hit, or whiff. So it is sort of stance related, but only because of the properties of the opponent getting hit. In other words, this is a 3D game without the ability to move in the 3rd dimension, and as such it doesn't have standard "2D" hitboxes. The characters are literally hittable where their character model is, but this is one of the only examples anyone's found thus far of a hit not resulting in the exact same animation every time it strikes the opponent.