from being a selfish brat mentally to a robust and caring father that will go to any lengths to protect his family and loved ones

the first loss against his father which led him to be kicked into the capital to grow, the first killing of people/humans on the continent he got teleported to, the appearance of one of the main driving forces (Orsted) for the last third of the novel, a certain misunderstanding that resulted in him staying alone for a good few years, the loss of his father, the loss against Orsted again when trying to defend his family under the influence of Hitogami, and the loss and death of one of his friends after his betrayal. Just to list some.

Badigadi

The main focus, Rudeus is a tr*sh in his previous life. He did something that most people think as disgusting. Even so, it's there are more twisted character out there, and IMO how morally bad a character is, it shouldn't effect their rating so, the other people that shouldn't judged this novel solely by his shortcomings. But rather how the author potray the character, and his interaction to the other character and the world. And this Muhsoku Tensei succeed splendidly. As I said before, the main character Rudeus starts as a failure. His perversion and trauma towards the world outside is what leads him to his death and this doesn't change after his reincarnation, not immediately. Roxy is the one who helps his outside world trauma, but his perversion needs a longer time to be corrected or rather 'tamed'. By the time the story begins to show the final plot, Rudeus has changed from this pe*verted NEET into a proper loving father. Not a perfect father, but a good father who thinks about his family first. This doesn't only happen to the MC. The other character, also experienced the same changes. The characters helps each other on their growth. Even for characters that wasn't given much show time, they have their own ego, their own priority. This is what many writers forgot, that each character is their own protagonist in their own life (You too).

The world is big, but not necessarily full of information. The world is expanded little by little as the character adventures. The things that are explained are not wasted information. It may not seems making any sense at the short run, but will at the later stage. The world itself, while not completely original, is unique. There are no useless game like menu. Magic and skills (not the game counterpart) is explained logically. This makes the MC very strong (but not like other isekai MC). While he has that laplace factor, he also did an efficient way of training which explained why he is that strong. This means the MC is strong but not special and his students are much stronger than the norm (albeit not as strong as him).

This is, I think the hardest part to get right in a WN. Unlike a normal Novel or even LN, most WN are written as a hobby by the author. This often leads to story that proceed as they pleased. However, this is not really the case in Mushoku Tensei. I will not say that the pace and climax in each volumes are perfect, but they are above standard. The pace is reasonable for a WN. Not too fast that you got overloaded, nor too slow that it bore you. Most of the things that the characters do will have impact to their story and development. Seemingly unnecessary things may actually be something important.

This story is a story about a person named Rudeus Greyrat. The story main problem starts not that early. The author gave the reader a chance to know about the MC and peoples around him especially the important ones. Build his relationship with the other character enough so that you can understand his feeling without feeling forced when the time comes. Then the mass teleportation happened. This what leads things goes awry. Things that happened mostly is because the mass teleportation and hitogami at the later stages. There are many 'antagonist' that stood against the MC. But here is what I love from Mushoku Tensei. The antagonist aren't that bad. I mean, bad people do exist (like s*ave dealer). But they have reason. Even the main source of problem, Hitogami, only tries to save himself. There are even antagonist that simply is in different faction and the MC actually really hate to fight them. This is more real, than stories that just throw out villains for the hero to fight. The story ends a few years after the last fight. I think it resolve just right as the MC is what the story about. He already changed to the good. No more enemies that poses real threat to his family. No more things that worth to be told about Rudeus Greyrat. It is time to pass the baton to the next generation. In a sense, Mushoku Tensei is a prologue to the main story of the fight between Orsted and Hitogami, like the author said.

The only thing I despise in the story was the Aisha arc of the redundancy chapters, however thankfully the author is going to retcon and/or rework that part (not sure if it is still canon as it was deleted but you never know)