Like I said before, I'm not saying that theory is correct, I'm just saying the cutscene you pointed out does not prove it wrong.
Regarding "consistency", I think it's quite a stretch to think that because a single cutscene shows some blood, every other cutscene automatically needs to, otherwise any sort of attack is automatically a weak, inconsequential attack.
The scene where Squall loses blood is a very key scene which ends up giving him the scar, which is very prominent on his face. As such, it doesn't surprise me that they emphasized this with a bit of blood spray.
But there are plenty of other instances of people being slashed in the game, with no blood whatsoever. How about in Deling when Squall jacks that car and blasts through the barricade, and starts slashing fools up. No blood there.
My point is, that scene with blood was the exception, not the rule.