Chibixx

Add shigeno goro's gyroball or a pitch that make batters knee buckled. Also I think it is weird that he can't field or bat as a former pro baseball player. Or that he can't use any of his arsenals of pitches he had when he was a pro pitcher. The story would had made more sense if he was a person that was interested in baseball like a fan but had no experience and then was reborn in Ace of Diamond and had to learn from scratch.

I also recommend Hitman Reborn.

How about adding a manga/anime about a smart MC? Like Death Note, Code Geass, or No Game no Life. It can show them that sometimes brain is more important than brawn to the people of One Piece. But if you are still wanting to add an action/tragic manga MC I also recommend D gray man.

Add Jaina Hudson aka the White Rabbit.

This is like your sixth attempt at a mushoku tensei novel at this point. Maybe this novel ain't for you. Why not choose another novel or anime to do a fanfic instead? Something less complicated and something you know more about. I honestly see no hope in you completing a Mushoku Tensei novel. No offense, but the results speaks for themselves.

Didn't you already did a rewrite for this? Why didn't you just start a new one instead? And before you did that rewrite you still only update once a week so when are you actually going to finish a mushoku novel. If you don't think you can finish one just move on. I honestly think you should just move on to another anime or novel to work with on a fanfic. On all of your mushoku novels, you basically stop at the same spot each time before a rewrite or drop it. Do you know how frustrating it can be waiting months for you to speed up the plot to the teleportation arc just for you to drop/rewrite it each time. This happens like three to four times now. Tell me author, what is your goal for this novel? Are you actually going to complete it and update more or just leave your readers hanging all the time. Tell me so that I either keep this novel in my library or just drop it.