It could be argued that The Mandalorian didn’t need to bring in Luke at the end of season 2 as a Skywalker-ex-machina. It could further be argued that the series could have kept Luke out of sight and only mentioned him in dialogue so as to not take attention away from the main characters. Maybe they should have waited two more seasons and then featured a Luke played by Sebastian Stan (by far the fandom’s most popular Young Luke fancast). Some have even argued that Ezra Bridger should have been the Jedi that saved Grogu in “The Rescue.”
Ultimately, all of these quibbles are fun to talk about, but the larger point remains: even if the series had decided to send Ezra instead of a Skywalker, at some point, Luke’s existence would have to be addressed somehow.
When Mando teamed up with Ahsoka Tano, she basically spelled it out: “There aren’t many Jedi left.” In 9 ABY (After the Battle of Yavin), the year in which The Mandalorian takes place, we’re basically only dealing with Ahoska, Ezra, maybe little Jacen Syndulla, and Luke as far as we know! Of those four, Mando had already met one of them leading into the finale. Meanwhile, Ezra still seems to be missing after the events of Rebels, and Jacen Syndulla is a little kid in 9 ABY. This means, if we’re putting all the toys in the toybox in the correct order, logistically speaking, Luke had to be the Jedi to find Grogu, especially at this moment when he’s already on a quest to rebuild the Order and recruit new students by this point.
Imagine you were writing a Sherlock Holmes fanfic series about Inspector Lestrade’s early years in Scotland Yard. At some point, that series is going to have to introduce or mention Dr. Watson or Sherlock Holmes because they’re major players in Lestrade’s life. That’s the situation The Mandalorian was in. Had the show been set during the High Republic era, or 5 years before The Force Awakens, it’s possible it could have gotten away with never dealing with any Jedi. But once The Mandalorian made its main storyline about Mando finding a Jedi to train Grogu, the show couldn’t just ignore the most important Jedi of its era.
Could future Mandalorian seasons (or the new Ahsoka series) go a bit deeper into the canon and bring Ezra Bridger and young Jacen Syndulla to live-action? Yes! And I think that’s exactly what will happen. By bringing Luke into The Mandalorian, as well as so many other popular characters, Favreau and Filoni have sent a very clear message: the Star Wars TV series won’t avoid other parts of Star Wars canon, even if those elements are messy, complicated, or loaded with nostalgia. The story is the story, and the characters are what they are.