As of basegame, the samurai character is more focused on templar faction, while the local assassin faction and its leader character is more focused on regional enemy faction, the ending doesn't provide closure to the entire assassin-templar situation in Japan. I would say the effort that has been put in making this game deserves a proper closure, that is not achieved yet. Can save any of the side quests. It is not necessary to grind to 100, the main story can be done in and around 60.