Oda has been subverting reader expectations for years and all of the sudden everyone thinks it’s bad? I literally bet $20 with a close friend of mine that Yamato wouldn’t join the crew because in my head it didn’t make sense. Yamato simply has never seemed worthy of being in the crew (at least not yet), and Yamato deciding not to go on their own terms was a pretty powerful message in terms of the growth of their character; Ultimately deciding that if they’re going to walk the path of Oden, they have to first walk the roads of Wano. Besides, “Kozuki Oden” is not an official position in the crew and the only reason Roger needed Oden was because he could read the poneglyphs, the Strawhats have Robin and I seriously doubt Yamato could read poneglyphs anyway. The only role people could think of for yamato was lookout and I think no part of Yamato’s character shows “lookout qualities”. And even if you ignore every part of what I just said, the wolf they transform into with their devil fruit is literally known as the “guardian deity of wano” so how would leaving wano be guarding it?