Spoilers ahead for the finale of the Star Wars: The Clone Wars animated series.
Star Wars has pretty neatly tied up the loose ends of the prequel era with the series finale of The Clone Wars. While fans have an idea of what happens to the Order 66 survivors down the line thanks to the original trilogy (as well as Star Wars Rebels), the 15 or so years following Revenge of the Sith for them are largely blank... for now. Ewan McGregor is reprising his role as Obi-Wan Kenobi for Disney+, and the end of The Clone Wars means it's time to look ahead.
The live-action Obi-Wan Kenobi series will be set eight years following the end of Revenge of the Sith, and therefore well ahead of the events of the original trilogy that brought Alec Guinness' version of Obi-Wan into the galactic action. The show will take place closer to the end of the prequels than the beginning of the original trilogy, so it's fitting that Ewan McGregor returns to the role of the Jedi Master.
With a TV show on the way, it's probably safe to say that Obi-Wan's years between dropping off baby Luke and appearing in A New Hope aren't going to just be years of quiet exile and meditation. Plot details may be shrouded in secrecy for the time being, but based on the end of The Clone Wars and the original trilogy, there are some things that have to happen.
Flashbacks To The Clone Wars
Obi-Wan was clearly still haunted 19 years after Order 66 when A New Hope picked up, so it would be downright unnatural if The Clone Wars aren't on his mind after only eight years. Flashbacks to his final years in the Jedi Order (even if in the forms of dream sequences or visions) could allow the Obi-Wan series to bring back familiar faces without resurrecting characters or retconning twists. The Clone Wars built the Obi-Wan/Anakin brotherhood to the point that Revenge of the Sith feels all the more tragic, and it just wouldn't be believable if Obi-Wan isn't thinking about his fallen friends.
Rumor has it that Hayden Christensen will return as Anakin Skywalker. Since Vader will still be a couple decades and four movies away from returning to the light and dying, it wouldn't be as a Force ghost. Flashbacks could showcase what people loved about The Clone Wars and prequel era, and the contrast with Obi-Wan's current situation could be powerful. Ideally, Disney+ would pull it off by creating new content rather than playing clips of Revenge of the Sith while Obi-Wan has a nightmare, but eight years presumably alone on Tatooine likely didn't give Obi-Wan much closure.
Training With Qui-Gon Jinn
When the surviving major characters of The Clone Wars parted ways in Revenge of the Sith, Yoda told Obi-Wan that there was more training for him to do with the help of his former master. Qui-Gon Jinn had of course died way back in the climax of The Phantom Menace, but The Clone Wars revealed that he'd found the way to retain his identity after death and return to communicate with the living. Basically, Qui-Gon the Force ghost was going to teach Obi-Wan how to become a Force ghost.
With Ewan McGregor starring in his own series, what better time to show that Obi-Wan was busy doing more on Tatooine than watching over Luke? The best-case scenario would be for Liam Neeson to reprise his role as Qui-Gon for some on-screen appearances, but even voice contributions could work. Neeson voiced Qui-Gon for The Clone Wars, and reprised the role (albeit briefly) for Star Wars: The Rise of Skywalker. At the very least, Qui-Gon would probably be a sympathetic ear about Anakin.
Old Ben Kenobi
Back before Star Wars was anything other than one movie, the legendary Obi-Wan Kenobi was introduced as Old Ben Kenobi. Owen Lars described Old Ben to Luke as a "wizard" and "a crazy old man," then said that Obi-Wan died around the same time as Luke's father. The rest of the movie proved that this was only true from a certain point of view, but Luke had no problem believing that Old Ben was somebody other than Obi-Wan, and he had clearly encountered Old Ben.
Even if Obi-Wan Kenobi's Tatooine alias of "Old Ben Kenobi" is about as thin as Yoda deciding to give Luke the "Skywalker" last name and hide him from Darth Vader on Anakin's home planet, he evidently did build a persona as a Tatooine local rather than an exiled Jedi. Honestly, an Obi-Wan playing his part as Old Ben could provide some humor to what could be a pretty somber series, since Obi-Wan probably doesn't have a whole lot to laugh about.
Interactions With Luke
Could Disney+ really deliver a live-action series starring Ewan McGregor as Obi-Wan Kenobi, set between Revenge of the Sith and A New Hope, and probably taking place at least in part on Tatooine without showing 8-year-old Luke Skywalker? As mentioned, Luke was at least familiar with Obi-Wan as Old Ben, and Star Wars Rebels proved that Obi-Wan was known to literally watch over him from afar. Owen seemingly wasn't an Obi-Wan fan, but hey, maybe they were on better terms at this point in the Star Wars timeline!
Luke might not have been bullseye-ing womp rats just yet at 8, but who wouldn't want to see him when he was just a desert ragamuffin on a moisture farm? Casting a young Luke Skywalker would be a pretty big deal, since Mark Hamill has had a firm grip on the character throughout the saga. If a young Luke does appear on the Obi-Wan series, I just hope Star Wars fans are a lot kinder to the young actor than they were to Jake Lloyd back when The Phantom Menace released.
Obi-Wan Learns Anakin Survived
Admittedly, this one is somewhat unlikely given that Darth Vader has presumably been rampaging through the galaxy on a hunt of surviving Jedi for the better part of a decade by the time the Obi-Wan series picks up, but it would be great to see. Obi-Wan learned that Anakin had been renamed "Vader" in Revenge of the Sith via gruesome security hologram, but as of the end of the movie, he didn't yet know that Anakin had survived their duel on Mustafar.
After leaving Anakin for dead and taking his lightsaber, Obi-Wan would have had every reason to think that he was no longer a threat. Learning that Vader had survived and become a murderous villain would be rough on poor Obi-Wan, but it obviously happened at some point, and Ewan McGregor would surely crush such a scene. This could happen via flashback, or maybe the show could just establish that Tatooine is enough of a backwater that the Vader news just didn't hit Mos Eisley for eight years.
Familiar Faces Show Up
The Obi-Wan Kenobi series will be something quite different from The Mandalorian, insofar as the focus isn't going to be entirely on new characters. Obi-Wan is arguably the most pivotal non-Skywalker character in the whole saga, so even if most of his friends and allies are dead by the time his show picks up, why not feature some familiar faces? I don't just mean Owen and Beru and the cantina band, but others could show up with contradicting current canon.
In fact, given that Boba Fett and Ahsoka Tano have reportedly been cast for live-action appearances on The Mandalorian, why not throw them back in time a couple of decades to appear on the Obi-Wan Kenobi series? Even cameos from some lesser-known Star Wars projects would be welcome, like Solo characters or Star Wars Rebels characters. I wouldn't be shocked if Obi-Wan and Yoda have a long-distance Force chat; hopefully some more familiar faces can appear without pulling focus from Obi-Wan himself.
Unfortunately, Star Wars fans won't get to see Ewan McGregor back as Obi-Wan with episodes of his solo series for a while. Production was set to begin in early 2021 on the show, and it's possible that could be pushed back due to the industry-wide production halts in recent months.