In fact, common sense supports the notion. Let's look at an example
Here. (Watch the whole thing). Could this fight scene work under your ruling? In under six seconds at a time, he attacks multiple targets with only one sword.
This fight scene would be impossible to replicate in D&D with your ruling.
Sorry, but I can. I can't spot a scene in this fight which lead me to think the guy is attaking more than his fair share within D&D and my own suggested rule.
Here how I see the fight so I can prove it to you: the first two guys charge the samurai. Obviously, charging require that they do it on their own turn and not the samurai turn. So he's simply using his attack of opportunity here and kill them on the spot. The fact that he attacked twice mean that he have some mean to do at least two attacks of opportunity in the same round (or maybe cleave can work in the opponent turn? I never checked that to be frank) which can be easily achieved with a specific feat. Next, the samurai move and hit a guy, killing him. Again, cleave: he kills the other guy in range, getting a free attack on him. Then the scene breaks and when it focus back to the samurai we see him again in his turn killing a single badguy. Then one of them attack him and the samurai block, which can easily be seen as the badguy moving in range and attacking, failing to hit. Once there, he graple the badguy, throw him down and coup de grace-ing him. I can easily see that in D&D as happening in two turns of 6 seconds back to back. The next guy, who jumps into the scene very fast, hold his saber over his head. Again we can assume he was charging and the samurai win the attack of oppurtunity, killing him on the spot. Then yet again someone charging by the samurai and dying...
The next scene is complicated to explain in D&D term. The scene take place in slow motion though, and watching it again I notice that the second guy is not actually in range of the samurai while he's somehow preventing the first guy the use of his weapon. At first I thought he threw his own saber in the badguy foot but watching closely I think he simply bury both weapons together in the ground. So again, two turns here: he prevent the use of the weapon of the bad guy (probably a feat here, I don't think it could be explained with basic rules at all as far as D&D is concerned.) and then dodge the attack of the second guy in the second guy turn. Then he proceed to kill the first guy with quickdraw (or even normal draw if you want, using his move action), use cleave again, and kill the second one.
The next guy die because the samurai use his dagger as a throwing weapon and kill him. No issue here?
Then, next guy. And yet, another charge. The charging bad guy not only can't overcome the samurai AC but I'd be inclined to say that he even critically failed because he loses his weapon. However, the samurai miss his attack of oportinity this time as he don't kill him outright. The charging badguy get his weapon back for dramatic effect, maybe a feat could do that or maybe the samurai simply wait for him to take it back for honor sake or whatnot... The samurai immediatly one shot him again. It's getting old as far as I'm concerned, I feel like I'm describing a very high level fighting a bunch of thugs level 1. (Actually that's probably it!)
Then, the last guy. This one I thought was way higher level than the others but... He might be, but still so low in level in comparison to the first one that it doesn't matter. Maybe a matching CR rating, which usually result in an easy to moderatly victory in normal encounters? Anyways, this is slightly tricky because both fighters seem to contest in some kind of strenght or grapple action. I don't think you can actually grapple holding a two hand weapon at the same time so I'd be inclined to say that it is simply the bad guy attack round which is blocked by the samurai (failed to win tohit versus AC). The the samurai one shot again the guy. Surprising at this point (sarcasm). And the combat scene end up with the samurai coup de gracing the guy who don't defend himself. I'm at work right now and I don't use sound but I'm guessing he his another bad guy or his old master or whatever? Not really important to be frank.
So there. This is how I describe it. Rather easily, using very simple and basic combat mechanism too, rather low level feats even. In fact, I didn't even notice if there was some part relevant to my question inside the video...
I assume you think there is though otherwise you would not have mentioned it to me in the first place. I'm not sure where you wish to go from here then? As far as I'm concerned were in the same deadlock than before.
If the appeal to logic does not work, what about the monk? The monk has only unarmed strikes. Can he flurry? The wording is:
Quote from: SRD
When unarmored, a monk may strike with a flurry of blows at the expense of accuracy. When doing so, she may make one extra attack in a round at her highest base attack bonus, but this attack takes a -2 penalty, as does each other attack made that round.
Monks "may make one extra attack in a round," but are not explicitly stated to be allowed to use the same weapon for that extra attack.
All I see here is a mechanic extremely similar to the one which give an extra attack to the fighter at level 6. One extra attack with a weapon, except that it is a class feature (feat) which grant it.
Second, this is a flurry of blows. The monk is a martial artist, it is more than fair to assume it is either a fist or feet attack or any other kind of unarmed strike I guess. This is using a natural weapon and thus is not the same thing: it relate to monster weapons more than 'normal' weapons. The fact that it is a class feature even more accentuate the fact that it might not fall within normal combat mechanisms too.
This means, by your ruling, that a monk needs to use a new weapon for each strike in a flurry.
No, it doesn't even apply to this situation. Because flurry of blows is a feat. I is not part of the normal basic combat mechanism, which is what is really discussed by my ruling.
Anybody can do a cleave, for example. Why can't everybody do it in normal combat without possessing the feat? Because the fighter specifically trained for that, to recognize the events leading to the use of this feat and using it every single time it is possible or convenient to do so. This doesn't cancel what I just said though: everybody can do it. It is simply that Mr. NextDoorJoe will only use an attack similar to Cleave once in a blue moon with most of his occasions lost because he don't capitalize on them or even realize they are there. So the basic mechanics of combat simply take that for a normal attack and ignore it.
Flurry of blows is exactly the same thing. Everybody can move their arms very, very fast. But if you don't do it right it won't work, or you'll hurt yourself, your opponent will take advantage, etc.
To be frank, I think taking examples here and there lead us nowhere. We probably both agree without an iota of difference what Flurry of Blows does and how it works in D&D, while the real issue I am bringing is not there. Like I said, the real issue is in the basic combat mechnics rules. Which are way too vage and easily misinterpreted. We could talk all day long running in circle without being able to prove or disprove eachother without a shadow of a doubt. That's basically why I'm, again, looking at the rule which specifically state what I'm looking for.
If there is simply none I think it is really an omission of incredible scale in the part of the writters.
It's okay to admit you were wrong. In my gaming group, we played for five years under the assumption that you can only make one sneak attack per round. Upon looking it up, though, we found out that that was just a really sucky house rule. I admitted it and DMed according to the actual rules. Sometimes, an assumption you made long ago makes you think it was actually the rules, but isn't!
Yeah, I hear you. I completely agree. But in this case it is not even a case in which I absolutely want to be right. I said it in one of my first post, my plan is to gather all the info I can on this and hope to find the small tidbit of info which I'm looking for so I can agree or deny my current dillemna. If I can't I still plan to agree to it and give it to my players anyways because they were pretty ticked off.
This whole argument between me and my players should never have escalated to the level it was either. I'm expecting one of my players simply wanted to achieve something out of game with it and used it as a scapegoat. This is really what bother me the most about the whole thing. To be right or wrong? I don't really care.
[skipping the rest of your post because I already answered it above]
@Veekie: I won't answer to your post right away because I'm at work and thus don't have much time. Also, you are mentioning a lot of sources at the end of yoru post which are completely new to me. As I said before I currently restrict my players to core and I never actually perused those feats or skills in particular so I'd have a hard time studying what you want to say without taking my time finding and understanding it.
That or I don't recognize the feats because they are in English. Are all of those core?
So, just wanted to say that I'm not ignoring you after this long post.