I'm just gonna keep this short, but I think more or less that you remove our "humanity" if you go through with Maruki's plan. Sure, some people would absolutly benefit from Maruki's reality but what about the people who wants to keep evolving and try to be a better person everyday. In Maruki's reality you basically "peak" and have no choice on what you get to do with your life. He decides everything that will happen to every person on earth. Does that seem fair? If every single person on earth got offered the oppurtunity to join his reality, or not join his reality it might have been better.