Don't get overly pedantic. The point is that many of the codes of honor will create a degree of contention at the gaming table that a GM will have to deal with to some extent.
It's part of why many aren't included.
Anyhoo...
To get a Code of Honor included, it needs to be consistently enforceable across multiple GMs (which includes being within the 'scope' of Missions play), it needs to be worth the points that are being given, and the level of potential inner-party contention that it causes has to be 'easily' mitigated.
All 3 of these need to 'Yes' for the Code of Honor to work.
So let's look at one that's allowed:
Assassin's Creed
Is it enforceable? YES! The restriction is black and white. The consequences are black and white.
Is it worth the points? Leaving witnesses and having to really focus on not employing (even accidentally) lethal damage arguably worth the 15 points.
Is the potential for contention amongst player groups easily mitigated? The restriction is that YOU don't kill anyone, not that your fellows don't kill anyone. What do you care if those rank amateurs leave a trail of bodies? If you do decide you need to kill someone and end up failing your Charisma + Willpower (4) test... what's the likelihood that someone in the party is going to physically force you to murder that person? Nil. The potential for inner-party contention is minimal.
Now let's look at one that isn't allowed:
Bushido 2.0
Is it enforceable?
Well... how are we defining the 'superior' in this case? Is it Mr. Johnson? Then yeah...
Is it another PC? OK, yeah.
Is it some NPC off books? OK, sure.
Is it worth the points?
If Mr. Johnson is the superior? Not really, Missions are generally written with the presumption that this is what you're doing anyway.
If we define the 'superior' as a member of the group, also unlikely to be worth the points. It is presumed that the team is working towards a singular goal and that your personal interests in the moment will almost always align with the 'leader'.
If we define the 'superior' as an off-screen NPC, then absolutely not... there is no mechanism to employ NPCs that aren't written into the Mission (this is why you can't take 'Ward' for example)
And finally, is the level of contention 'easily' mitigated?
If Mr. Johnson is the superior and the team decides to go off-book and you fail your Charisma + Willpower (4) roll, you absolutely must oppose the team. This is literally a PvP situation.
If another PC is the superior and orders you to do something and you fail your Charisma + Willpower (4) roll, you absolutely must do what that player tells you to do, removing your agency in a manner that could have little to do with advancing the mission.
If it's some non-Missions NPC, it would likely be mitigated because it won't ever come up and if it does, then the GM has taken an active hand in this and hopefully in GM we trust and he isn't railroading the team into some weird PvP.
Sooooo.....
We have a
Y / N / N
Y / N / N
Y / N / Y
There is no plausible situation where all three of these are "Yes" and we can't make any good cases to lessen the impact of the "No's" to something that works for the Missions format, so Bushido 2.0 is not included.
So when discussing the ones that aren't included, you are trying to make a strong case for why all three of these questions are 'Yes'.
In many cases, mitigating concerns for one of the questions can cause another one to become invalid.
So... for each of the disallowed qualities you want us to include, tell me (and by extension, the SRM FAQ Team) how the Code of Honor can be enforced and is within the scope of Missions (that means that the enforcement doesn't call for the GM having to spend potentially a good portion of Mission time addressing the Quality), how it's worth the points, and how conflicts are overwhelmingly more likely to be peacefully resolved rather than cause a PvP scenario.
If the only issue is 'value', then propose a lower value and defend it (for these the FAQ Team may discuss if it's possible to include it at the lower value, for which we'll have to take other factors into account).
I also want to point something out:
In this discussion, anyone having a different perspective on what something means than anyone else is, in itself, proof that whatever perspective you have isn't as obvious as you think it is. Which leads to a question of enforce-ability.