So I'm writing a saga at the moment, and I'm unfortunately having to go back and revise my first book accordingly to my second because they aren't matching up so well. My issue is that I feel there's a disconnect between the books since the main characters are completely different. They do know each other, but I wonder sometimes if that's enough. Does anyone have any examples or thoughts to bring to the table? I feel like someone going from the first book to the second would be like: "Where in the world is the main character from the first book?" Because she doesn't show up in the second book except in references and the end.
There are other series, both books and other mediums, where each installment features a different protagonist. I don't think people are going to have a problem with it.
Most sagas have a different main character for each installment, it's the joy of reading a saga, especially when they all meet up for the grand finale. It's the norm, so you have nothing to worry about. Happy writing!
I'd say that's absolutely acceptable, and can even prove a really interesting shift. I love exploring a fascinating world through the eyes of different people, to see the same areas and locations through a fresh pair of eyes, and I don't think readers would be too put-off if you switch between protagonists with each new installment. But if you're going to switch them, make sure to close off each main character's story satisfactorily with the end of each book they star in! Nothing is worse than picking up book two, expecting to go back to the character who's story you want to finish, only to find out it's about someone else!
All of these answers are certainly reassuring, but yours talks a bit more about something I haven't thought about. For example, the main protagonist from the first book may end a development arc for her end on the first book, but she will later have more to develop in future books as a side character or as a POV character once again. Most but not all answers for her would be answered by the end of the second book. I feel like this is satisfactory for the reader but I could be wrong.
You can continue to develop your 1st-book protagonist as much as you like throughout other books! There's not a limitation like "they have to be complete by the end of the first book" or anything. BUT! In the first book, your protagonist will have a particular set of problems to confront, and growth to have--an arc, if you want to phrase it like that. But that arc better darn well be wrapped up nicely by the end of the first book. Everything that the first book starts, it should also finish (within reason), and any subsequent books can open new cans of worms and development arcs.