You don't seem to understand that the branch of Observation haki that allows you to avoid attacks and stop them is in fact intent sensing. Sanji dodging Katakuris attack was only due to him sensing his intentions even under such a stressful situation. When Sanji stopped Queen and Peros attack it was also an example of that since they weren't in his line of sight so the only way he could have stopped them was by sensing their killing intent, so no he does indeed posses the ability to sense intentions.
"Another variant of Kenbunshoku Haki allows its user to sense another person's intent to act in the immediate future (especially through bloodlust/killing intent within combat), allowing them to predict what someone is going to do, usually seconds prior, in what resembles a pseudo-form of precognition. However, it should not be confused with the actual, literal ability to see into the future which (as explained below) requires another level of skill entirely.
Naturally, this predictive application of Haki is highly helpful in battle, as the user, depending on their level of proficiency, may have a vastly easier time predicting the path of enemy attacks to either dodge or counter them. The more killing intent exuded by a given enemy, the more predictable their attacks, although great enough Kenbunshoku experts can predict enemy moves whether there is murderous intent or not".( referring to future sight)....This is off the Wiki
"The most important thing to remember is that every attack carries an intent, and a hint" - Rayleigh
Sanji not being able to activate his Armament haki is the same reason one could argue he rushed prematurely into a trap, simply put when it comes to women Sanji is easily manipulatable and often times is too overcome with emotions to make rational decisions. If Oda were to write Obv haki the way you want him to then no character would ever end up in any conflict, lets not pretend that Oda has been consistent with the way he portrays haki, especially Obv. Luffy can see the future and sense intent but he will still get hit with attacks and get caught in traps if Oda needs him to for plot purposes. "Had to asked a beat up soldier the location of the scabbards and of momo. And was incapable of sensing any of them", which proves my point that Oda isn't consistent with Obv haki and that expecting Sanji to be all knowing at all times limits what Oda can write, this does not negate the fact that Sanji's specialty is Obv haki and is more proficient at it than Zoro and maybe Luffy in certain branches. No character has shown the ability you are asking of Sanji, to know the location, intent, threat and condition of two separate groups of people no matter the situation or distance.....this is ridiculous and Sanji doesn't have to be able to do this for him to be highly skilled in Obv. "Couldn't hear the conversation any of the groups were having"...again this proves my point. Sanji was able to hear the conversation coming from the third floor in the BM situation but not this......not a Sanji issue it's just Oda deciding for Sanji not to for the storyline he has planned. Or one could say they were too far so he couldn't sense them which doesn't make him weak in Obv just puts a limit on it.....which makes sense.
One could argue that BM was hiding her intentions, a human is capable of that that's why it's easier to use Obv on an animal vs a human because one can deceive while the other cannot. BM in the field that she works in would be a master manipulator and capable of completely hiding her intentions maybe even to a point of believing her own act, this is something that cannot be ignored.
Also a gag moment doesn't lead to serious moments, if Nami punches Zoro so hard he is physically affected to the point of not being able to fight an approaching threat then that ceases to be a gag moment since it has in story purpose beyond comedy so please understand the terms you are using before using them.
