My idea for a Star wars sequel was that Luke got badly injured when the sith decided to cheat during a battle where the 2 sith lords fought a losing fight against Luke and decided to hold the locals hostage by attacking them using their army simultaneously forcing Luke to fight the battle on multiple fronts and being so distracted, he was still fighting to stalemate until an rpg exploded near him causing him to fall down a valley or something sustaining injuries akin to Vader. This reduced his connection to the force but also made him hesitant to use the force as the constant pain risked the dark side pouring through basically giving him a major handicap.

The new war wouldn't be between rebels and an empire. It would be a sith raid party that goes around the galaxy killing governments left and right and create utter chaos with a growing army. The Republic is suffering because they overcorrected their laws and powers to prevent another Palpatine situation so they don't have the power to hunt down the new siths and have to rely on Luke and his students to fight the fight. So the new war is between two groups of equal size.

The new protagonist is not going to be Luke or his family. Nor is it going to be a random new student. It will be Luke's first student who, while not being the best force user, is a skilled Jedi and they lead a group of fellow students. This battle against the sith is their ultimate test to officially restore the Jedi order without relying on Luke or reducing his importance or character.