Do we know roughly how many episodes each of the planned Star Wars series will be?
I'm not sure if the Marvel series will be any indication, but its interesting to see that Wandavision was 9 while Falcon and The Winter Soldier was only 6. I'm not sure if either of those is supposed to have a second season or if they're just meant to be setups for movies that are coming out in the future. I know Wandavision helps setup the next Doctor Strange movie, but I'm unaware of Falcon setting anything up.
I could see the benefit of both approaches, but from a selfish perspective I'd love to see The Mandalorian, and Kenobi, and some of these other series go on for years, especially if there is no movie tie in.
Wandavision was actually supposed to be 10 episodes in total, but they weren't able to do everything they wanted due to COVID-19. They ended up spreading the events of one episode across a few others to make it more cohesive. That's why the ending doesn't really feature certain characters like Darcy - she was on the opposite coast and couldn't get to where they were filming between travel restrictions and quarantine. It was rumored that Cumberbatch would have a guest appearance as well, but he was in New Zealand, so not at all feasible to get him back and forth in time. Senior Scratchy (Agatha's bunny) didn't have a payoff by the end, but was supposed to be some kind of demon and a scene was cut with him trapping the twins in the underground lair. But it doesn't really lend itself to a sequel - it was intended to get the character from Wanda to Scarlet Witch, bring back a form of the Vision, and introduce Photon & SWORD while connecting some past elements to the continuity (Darcy, Woo, the blip, etc.). Maybe even an intro to the Young Avengers if they can bring Billy and Tommy back somehow.
I thought I read somewhere that Kenobi is six episodes, but an hour in length. I think number of episodes is a little ambiguous and less meaningful given each episode has varying time lengths. FATWS was fewer episodes, but each was longer than WV, so similar amount of content in a more compact form I think. Not sure which I prefer - I felt like the shorter WandaVision episodes made it feel like a longer experience and enabled more cliff hangers. That FATWS episode where they go to Madripoor, find agent Carter, Walker gets the syrum and kills a badguy all in under an hour felt like it could have been 2-3 episodes. I don't think either of these are intended for sequels - as you said, they are plot movements intended to set up future movie events without having to go too far into the background/origin of slower paced events. That's been Marvel's strategy all along with the solo movies advancing the background development so team films can focus more on a cohesive plot/singular storyline.
Star Wars is a totally different animal. Where Marvel is pushing out different sized chapters of an ongoing mega-story, Star Wars is bouncing around the timelines filling in previously unexplored gaps. That gives them a lot more freedom to do multiple seasons because they're not trying to time multiple other projects off of each individual show. For example, Black Panther had to happen before Infinity War to establish Wakanda's tech and army, but they had to wait until Endgame finished to bring Spidey back from the blip for Far From Home. Kenobi, Mandalorian, etc. could be one season or ten seasons because there's nothing else immediately following the storyline to force an ending. Rogue One is the only modern release that really cuts off the potential for a sequel because it leads right into ANH, and even there they found a way to run a prequel instead. It will probably just depend on how well these shows do. I think Solo would have gone right into a sequel if it had been better received.
