Worstgen
Aside from the usual Sanji (and CoO) slander by Oda, I think there are some reasons why the SH don't "sense" Aramaki (and meet him) this chapter.
1. Letting Momo deal with it, to increase his confidence or authority
Maybe the SH respects Momo and wants him to build fame and credibility. This way Wano can truly be independent and can deal with their own affairs, not clinging to Luffy and co.
What wrong with this?
Admiral is peak tier combatant, if something goes wrong with the fight, Momo can be fatally wounded and that's bad. SH isn't that heartless.
2. To showcase that Momo+Scabbards can defend Wano
This way the SH can safely leave them for their next journey. Wano defending against an Admiral reassure this point.
What's wrong with this?
They can't even stall Kaido.
3. Showing us that Yamato is part of Wano/Scabbards, or will stay to defend Wano
Yamato realizing that Wano still have threats, and choose to defend Wano as Guardian Deity.
What's wrong with this?
From the start of Yamato's appearance, her dream is to set sail. One Piece is about freedom and accomplish your pursuit.
4. Momo will push Aramaki to Shanks
It's possible that Shanks appear just for chasing out Aramaki.
What's wrong with this?
Momo doesnt have the ability to push him there.
5. SH waits until some time later to sweep in together
It will be the usual case of allies getting overwhelmed and SH comes in to save the day.
What's wrong with this?
It means SH still need to babysit Wano. That's a bad showing for Japa.. i mean Wano.
6. SH didn't really notices Aramaki
Maybe the SH really don't get informed by the scout.
What's wrong with this?
Yamato is enjoying time with the SH. If she sensed Aramaki, Sanji should too.
Momo asking Yamato to stay out of the way, which means she shouldn't be informed in the first place.
1. Letting Momo deal with it, to increase his confidence or authority
Maybe the SH respects Momo and wants him to build fame and credibility. This way Wano can truly be independent and can deal with their own affairs, not clinging to Luffy and co.
What wrong with this?
Admiral is peak tier combatant, if something goes wrong with the fight, Momo can be fatally wounded and that's bad. SH isn't that heartless.
2. To showcase that Momo+Scabbards can defend Wano
This way the SH can safely leave them for their next journey. Wano defending against an Admiral reassure this point.
What's wrong with this?
They can't even stall Kaido.
3. Showing us that Yamato is part of Wano/Scabbards, or will stay to defend Wano
Yamato realizing that Wano still have threats, and choose to defend Wano as Guardian Deity.
What's wrong with this?
From the start of Yamato's appearance, her dream is to set sail. One Piece is about freedom and accomplish your pursuit.
4. Momo will push Aramaki to Shanks
It's possible that Shanks appear just for chasing out Aramaki.
What's wrong with this?
Momo doesnt have the ability to push him there.
5. SH waits until some time later to sweep in together
It will be the usual case of allies getting overwhelmed and SH comes in to save the day.
What's wrong with this?
It means SH still need to babysit Wano. That's a bad showing for Japa.. i mean Wano.
6. SH didn't really notices Aramaki
Maybe the SH really don't get informed by the scout.
What's wrong with this?
Yamato is enjoying time with the SH. If she sensed Aramaki, Sanji should too.
Momo asking Yamato to stay out of the way, which means she shouldn't be informed in the first place.