Except that's not what I'm saying. If historical consistency would be game-breaking or create issues with not replicating historical outputs (for example, France being nerfed because if it had historical equipment it would stop Germany every time), then it gives way to balance.
Bhutan having the capacity for a nuclear program is neither a historical input (Bhutan didn't have that capacity) nor a historical output (Bhutan did not, and could not develop one in the game's timeframe). Therefore it should not be in the game for either reason.
France being gimped is neither a historical input (they had more stuff) nor a historical output (they were not overrun by German superior numbers across the front in late 1939). An output without the historical input is not historical, and that's not a matter of opinion. History did not ignore causality, and that *is* what you're suggesting with the above.
In a normal HOI 4 game Bhutan will never produce a nuke during 1936-1948 right now, so I don't see the issue. If they somehow manage to grab more territory + people, it's somewhat more plausible, but still unlikely (and this still holds in the game, nukes take a lot of IC). If they somehow take 2/3 of the world having nukes stops being implausible at all compared to the rest of the scenario at that point.
Anyway, we might be arguing different things as a premise before this discussion. I am not in favor of buffing minor nations, they're already strong enough to WC in single player if optimized. That's more than enough. I would be opposed to the concept that Bhutan or whoever would still be incapable of producing nukes even if they, for example, full annexed the United States (which the game allows), because blocking nukes at that point would be silly and internally inconsistent.
Of course I am. The US simply can't be the powerhouse it was in reality, for instance. France can't be more powerful than Germany as in reality, because Germany needs to beat them close to hundred percent of the time.
That doesn't, of course, mean that every minor should be far stronger than in reality.
Buffing/nerfing nations for gameplay and refusing to buff/nerf nations for gameplay at the same time isn't a coherent preference set.
Now, since this is a standard there will be edge cases that you could argue either way, but that doesn't make a standard inconsistent or incoherent, that's just what a standard is. A judgment call based on some purpose or principle with uncertainty at the margin.
Standards in the context we are using them don't work that way. If your threshold for acceptability changes this way, it does not conform to a standard at all.
When a standard is "we only accept scores of 70 or higher to pass the course" or "you must have scored at least X on exam to be considered when applying", that is not a judgment call.
Similarly, the standard actually used in HOI 4 is that history is the theme. Conforming to historical outcomes is not, and neither is conforming to historical capabilities. There's no basis for randomly making exceptions. There is some consistent basis for denying Bhutan nukes from a gameplay perspective...but the game already does that without needing to self-inconsistently invoke history in the discussion. The rules alone are good enough.
Nations with terrible IC + few research slots can't nuke anything in meaningful timeframe in HOI 4. That's true for all nations and is adaptive to situations that actually present in the game while being consistent with the rules elsewhere. Bhutan isn't an exception and doesn't need to be. Neither does France, Argentina, or USA.