I disagree with so many posts above.
First. What is fan service? When it is bad and when is it good? In a hugely interconnected universe like Star Wars you are going to have old things show up. One of the few things I hate about the prequels is the lack of OT and PT aliens. Too much effort was made to make it different without throwing in a few familiar faces. So you can go too far the other way. If Fan Service must always be a bad thing than not every appearance of something familiar is Fan Service.
Also, too many are objecting that a couple of episodes that aren’t focusing on the titular character. This is not an episodic series, but a larger story told in multiple episodes. Boba Fett’s story starts with episode 1 of season 2 of The Mandalorian. Boba Fett already invaded that series so this is just continuing that story and we have episodes that focus on Boba’s past and now episodes exploring what Din Djarin is doing. Why? That is the question you should be asking yourself. This story is building to a conclusion that reportedly is epic (and we shall soon see if it truly is) and they are gathering characters for that conclusion. What form that will take we don’t know, but there are all sorts of interesting possibilities.
And the big question from the end of The Mandalorian season 2 was how the series can continue without Grogu. The series was really Long Wolf and Cub set in Star Wars and leaving Grogu with Luke for too long ruins the dynamic of the series. And Grogu’s ties to Din Djarin pose an issue for Luke. He has learned from Yoda. He has likely learned a few things from Ahsoka (it is obvious they did not just meet). We don’t know what he may have already found in the post Empire world about the Jedi Training at the Temple on Coruscant. What we do have is Luke in TLJ saying that the TPM era Jedi were flawed. So does Luke learn from Grogu, or does he cling to the TPM era Jedi teachings? Does Kylo Ren fall because Luke let himself be blinded by the idea of restoring the Jedi, or will Grogu teach him that it is not attachments that are the danger, it is the fear of loss that is the danger.
So there are a lot of great story telling possibilities here. It does not all have to revolve around Boba Fett as long as this series is revolving around Boba’s efforts to become and secure and defend being Daimyo of Tatooine. If that is his intent as we saw at the end of The Mandalorian Season 2, then the story telling is spot on. You have a bounty hunter who has survived for a decade since he fell in the Sarlacc and been rescued from the desert by Tusken Raiders aiming much higher and striving for something different. So many of the complaints I see about Boba’s characterization are tied to his new line of work differing form his old line of work.
I think some of the different threads of story will come together in the finale. And we will see if it will be carried on for a second season. We know The Mandalorian Season 3 is on the horizon.
Also, complaining about animated characters and how they are transferred to live action is sometimes silly. Cad Bane is blue. He is represented by a man in a mask like his fellow Duros were in ANH and his skin color is in line with the other live action appearances of his race. Same with Ahsoka. I wasn’t very pleased with how she looked in Rebels (a lot of the character design in that series was very stylized) and her live action appearance here is closer to her original look in The Clone Wars. Plus it is live action so it is bound to be different. I somewhat expect Asoka to show up next week and for Cad Bane to be defeated and escape. His appearance here is very organic (other than he is really old at this point) because this is the sort of thing he does and it makes sense for the Pike Syndicate to hire him.
I think the series could have been better arranged. I think they should have started it out with Boba Fett escaping the Sarlaac and just done a chronological story instead of flashbacks. I think there should have been some other scenes of Fennic recruiting muscle in the last two episodes and saved some of Din’s story for the his next season. But overall I like where the story is going and I love the characters and how things are intertwining. Star Wars is all about things being interconnected and I love that Filoni (who has taken many lessons from George himself) crafts such excellent long term arcs. There are still a lot of unanswered questions in the post ROTJ world that I think these series are going to address.