And he's said that he hasn't been able to spend much time with his family, in the past -- so I assume the breaks are partly to let him do that.
Doesn't Jump force breaks on Oda as he overworks himself?
Yep. Early in Dressrosa he worked himself into the hospital.
Gyababababa! Jump is the World Government and while I can't read the Poneglyphs myself, "Robin" has filled me in.
Oda definitely couldn't have had Sabo be a pirate also, otherwise there's no way Ace and him wouldn't have crossed paths at some point.
While you're right that Sabo is giving us a different perspective, we're really not learning that much about the Revolutionaries at the moment and I have a feeling it's going to stay that way until it's time for Dragon and Luffy to talk.
"Arguably", Ace's tattoo is an example of a "retcon". Originally the tattoo misspelling was just a funny joke making fun of Ace for misspelling his own name/having to fix his tattoo to spell his name right. Until Ace was killed and Sabo was added, there were no other story reasons to indicate Ace's tattoo had any other significance. Because of this, there's no reason to believe Oda "always had this planned" outside of getting too caught up in the fandom/"OMG Oda". It's similar to arguments between people who believe Oda always had Haki planned vs Shanks having a badass moment all those years ago and Oda crafting a story/a concept around that moment later in the story to enhance it.
As for the tattoo, my feelings are from the tattoo's introduction. Up until the Sabo story line, there was never a "explanation" for the tattoo misspelling. And that's because there wasn't a need for it. When the average reader saw the tattoo, the typical reaction was along the lines of "Haha, the tattoo artist must have messed up Ace's name while making his tattoo/the tattoo artist thought Ace's name was spelled Asce". It was a visual gag, and there was nothing more needed to be explained to the audience for years, which leads me to believe that was Oda's original intent. Had this tattoo had any sort of significance years before Oda introduced Sabo, then there are absolutely no story reasons why he couldn't have hinted at the tattoo having more meaning. Even something as simple as...
"Hey Ace, why is that S crossed out on your tattoo? Did you forget how to spell your own name?"
"The S is to remember someone I lost a long time ago"
...would have gone a LONG way story wise.
Regardless, as others have also said, retcon or not, it doesn't really affect the story outside of my feelings that Ace's death wasn't originally planned and that Oda created Sabo because he still needed a big brother character to complete Luffy's story.
OK I've got to jump in on this. I'm going to say a lot without giving sources but just bare with me for a bit before I look things up.
I do understand your feelings about Sabo just seemingly appearing out of no where and at the last second along with the tattoo not having any significant meaning. A lot of that is debatable. But Oda has gone on record saying that Ace's role in the story and his death were planned right from the start. He is a big brother-role model trope for the main protagonist and his name is Ace for crying out loud, the Ace of Spades is the card of death. As far back as Enies Lobby I remember people telling me Ace would die and that was long into the general consensus that people in One Piece do not die outside of flashbacks. I certainly didn't believe it even when the above was explained but hindsight is 20/20 I suppose.
So with that being said if Ace's role was planned right from the beginning I would not be surprised at all if the concept of Sabo was intended from the start as well. The whole tattoo misspelling fan theory was so commonly accepted that for years people just took it as fact. Kind of like when people say Oda said he doesn't kill characters when in fact he said he doesn't like to kill characters.
Luffy has been extremely consistent for 17 or so years when it comes to his past or anyone else's in the crew. He almost never brought up anything about himself and barely knows anything about his own crew mates beyond who they are today. Think how surprised the crew was to learn about Ace and then think how surprised they were to learn about Garp. I know you(Kreed) weren't really arguing this particular portion of the topic, just adding it in.
Learning about Sabo was no more surprising or retconning than say the Wind Mill Village that Luffy grew up in was only a tiny piece of this huge Kingdom that even Celestial Dragon's would visit.
I certainly would have loved a character to question the tattoo, but I could say that about a lot of things, Zoro's eye always comes to mind but we'll undoubtedly get that reason in due time. Oda may have wanted to name drop or hint at Sabo a little sooner and maybe like his intent to name drop Shiki the Golden Lion during the meeting between Shanks and White Beard, maybe he felt like it just wasn't necessary even during rare meetings between parties who would know who Sabo is.
Now I know I come off as apologetic for Oda and while everything has not been planned down to the T(he has said as much several times and boy I got some inside stuff that almost blew my mind) he does try to do his best to make things unfold very naturally and gradually.
Haki was very much intended from the start. Or even if Oda used Shank's defining moment and created something out of it he still dropped hints early on for years and years before he came out of the closet with it. But I dare anyone to say that Haki as we know it now is exactly what was intended. The first chapter was our first hint at Color of the King. A little while ago we found out that aside from a lost Usopp scene in Logue Town, Luffy was supposed to visit a fortune teller where he would be told he is marked with the color of a king. That would have also gone a long way in setting us up. Then you have Zoro fighting Daz Dones and the breath of all things. Right after we get Skypiea and mantra. Then of course by Shaboady and Amazon Lily things were started to get a lot clearer.
While Black Beard's Darkness Fruit has a leg up over Haki, the way Oda had Teach describe it makes it seem like Color of Arms wasn't a fully thought out concept. None of Teach's words during that fight contradict anything in the story, it just makes his boasting seem a lot less valid in hind sight. Then of course you have the blackening aspect that only appeared after the time skip. Even that we don't have a good explanation for yet, like what's the difference between the invisible armor and the black stuff? Hardness? Density? Oh and lets not forget Iron Body, the technique made famous by CP9. It seems like such a poor mans Armament in comparison. To be fair though Iron body probably still has it's value because it makes the entire body harden like steel while Haki seems to be just an out side(but way more versatile) coating.
Before Ace died I had already hypothesized that once a fruit user dies the fruit regrows somehow and someone else can obtain the power. It was the only logical explanation. The chapter Ace died I wondered where that flame power was going to go. The chapter White Beard died I wondered where the quake power was going to go. Oda has a way of making promises and living up to them even without directly saying anything of the sort. Luffy always said he could never beat Ace in a fight, not even once, and then White Beard being depicted as some sort of end goal character, it's only logical fans would assume that one way or another Luffy would surpass these people. Before Sabo was introduced I figured the Flame Fruit would be inherited by some sort of friend rival and that would be our flame flame VS gum gum. The chapter the 3 kids drank the sake I just knew Sabo would "die" then return and inherit Ace's fruit. In my head it was something Oda has wanted all along.