It's not about easy but Luffy's reasoning which is Oda's reasoning.
Luffy doesn't seem interested in Yamato. Oda has not put Luffy in a situation to observe Yamato for a defining moment for an invitation decision. They fought briefly, talked about Oden's Log book, split off, met shortly against Kaido, then split off again. At least let Luffy see Yamato's transformations. Luffy hasn't even seen a Mink turn Sulong. Why the avoidance by Oda?
How long does it generally take for Luffy to invite someone to be in his crew? What are Luffy's reasons to ask?
- Luffy was already contemplating inviting Zoro before they met based on Coby's scary description of Zoro. Made up his mind after seeing Zoro eat that dirtied sweet rice ball.
- Zoro approved of Nami's navigation skills before they met. Luffy invited Nami as soon as Luffy knew Nami was a navigator. Luffy took back the invitation when he thought she was bad. Reinvited when he realized she was not bad. Helps Nami after she runs away.
- Told Usopp to hop on Merry when they were leaving. I believe once Luffy knew Usopp was Yasopp's son that Usopp would be invited, maybe already a crewmate in Luffy's mind hence why it wasn't a formal invitation. Luffy accepts Usopp's apology to rejoin.
- Invited Sanji once Luffy saw Sanji was a good cook. Luffy refused Sanji's refusal. Rescues Sanji from Big Mom after Sanji ran away.
- Invited Chopper based off Chopper's 7 transformations. Nami invited Chopper because Chopper is a doctor. Luffy refused Chopper's refusal.
- Robin self invited herself because Luffy rescued a suicidal Robin were Robin's previous acts let Luffy determine Robin was not a bad person. Robin's ship role was hinted at the end of Alabasta and expanded once on board the Merry. Helps Robin realize she wants to live and rescues her from the World Government after she runs away.
- Franky has similarities to Luffy's shipwright drawing before Water 7. Invited Franky because the Franky Family wanted Franky to leave Water 7 because of Franky's bounty, needed a shipwright, and Luffy was pleased shipwright Franky built their new ship Sunny. Franky's dream also requires Franky to travel on his dream ship.
- Luffy almost immediately invited Brook on the spot. Brook had multiple attributes and connections foreshadowed throughout the series: musician, Laboon, and afro that Luffy summarizes. After accepting then declining, Brook reaccepts after his shadow was saved.
- Introduced in Arlong Arc. In Impel Down and Marineford, Luffy and Jinbe were together trying to rescue Ace. Afterwards, Jinbe helped Luffy cope with the loss of Ace. Later, the Strawhats and Jinbe save Fishman Island from Hody Jones where Luffy invites Jinbe during a memorable blood transfusion. After initially declining, Jinbe officially joins the Strawhats in front of Big Mom which Luffy is joyful about. It just so happens Jinbe is a fantastic helmsman which said position was introduced with Burgess back in Jaya.
The trend seems to be more build up for each subsequent crewmate. The later a crewmate joins, then the more setup has been displayed in the series. Where is Yamato's setup? A vivre card made for Ace that Ace gave one piece of it to Luffy...which is gone since Ace is dead. IMO, a better setup if Yamato were a future crewmate is if Ace would have also gave Luffy Yamato's vivre card saying something like "Free this person if something happens to me" or at least mentioned some characteristic of Yamato to Luffy. It gives us the reader something to speculate.
And the other invitees:
- Gaimon has a shrub afro. An Oda favorite.
- Crocus is a doctor.
- Dr. Kureha is a doctor.
- Vivi was a red herring for Robin.
- Iceberg is a shipwright.
- Old Tree Guy Zombie and Unicorn Zombie because ...? It never was explored.
- Kin'emon's legs for Luffy to be a centaur.
- Leopard Centaur because...centaur.
I ask again, what reason does Luffy want Yamato on the crew? From past experiences, it would be because Luffy sees Yamato as a good person. Well that's not a unique enough reason as Luffy knows plenty of good people that were not invited. Same principle with Yamato's strength. But since Yamato is a good strong person, Luffy may accept Yamato as a guest but another self invitation as a crewmate without similar depth like Robin's setup seems unlikely.
And did you just write future shogun Momo is not the successor of Oden, Momo's father and someone who was supposed to be shogun, but some random stan in Yamato is Oden's successor?
But that's not Luffy's (King of the Pirates) crew though...besides Whitebeard stated too many CoC users on a crew doesn't work per experience. The question is were they active CoC users before invited by Xebec or awakened as crewmates? IMO, it seems to be the former.
I could see Oda having some of the current crewmates awaken their CoC haki like Nami (Money Queen, Weather Queen, Queen of Witches), Usopp (Sniper King, God Usopp), or Sanji (Mr. Prince, Cook King) but inviting a CoC user right away is questionable as Zoro (King of Hell) just learned to use CoC with Enma. The readers have seen that growth from Zoro. Yamato would be a CoC throw-in. What is Yamato conquering? What would be a potential title?
Your reasoning for thinking Yamato will be invited is fanmade rules. It's all an analysis of our observations.
Going by past invitations, Yamato lacks foreshadowing, a known needed ship role, or connections.
I mentioned Usopp, Franky, Brook, and Jinbe because that part of their childhood can be explored, would be something fans would want to know, and gives depth to their characters. If Yamato has more to their character besides copying a character that didn't even acknowledge their existence or copying moves from the father they hate, then it would be nice to see but not sure it's something Oda needs to explore for Yamato as a crewmate. That resolution could be explored with potential partner Momo as they are linked with similarities.
Not really. The narrative is Yamato wants to ride Luffy's ship to explore the seas and be free. That dream would be complete once they sail outside of Wano. Not a likely scenario. So Yamato needs a more defined end goal. Maybe Oda's holding it for some grand reveal but I doubt it especially how Yamato blurts out whatever with no filter.
But we shall see. Just be ready to have your copium if Yamato doesn't join.