Personally of the characters I think Ranma would make the best parent. Others could probably do well if they want to.
As for corporeal punishment well that is largely about where in the world you live, some places accept it others do not. 23 countries have banned it and in several of them using it will get you jail time (USA is one of the countries more in favor of it what with it being legal for teachers to use it in 23 states -btw it is illegal in Japanese schools), but the USA is messed up country what with being one of only three countries on earth that still has a juvenile death penalty (other two are Iran and the democratic republic of Congo), the largest percentage of its population in prison of any country (quote: "no other society in human history has imprisoned so many of its own citizens."- California Prison Focus), and US prisons are so bad several countries refuse to extradite criminals to the USA because the prisons are considered to inhumane).
As for scientific studies on spanking, those show it is effective in the short term, extremely ineffective in the long term. "The more children are spanked, the more anger they report as adults, the more likely they are to spank their own children, the more likely they are to approve of hitting a spouse, and the more marital conflict they experience as adults." Spanking has been associated with higher rates of physical aggression, more substance abuse, and increased risk of crime and violence when used with older children and adolescents." -American Academy of Pediatrics
