That's a pretty interesting point of view,but I have to disagree on some of them.
-I don't think that you can actually compare Simba's and Kovu's past, they were too different to be compared as to who's was harder. Kovu spent his life being trained to take over the PrideLands,and he was with his pride,while Simba was convinced to be the one who killed his own father and got away from his pride,living his life as a rogue. Everything was taken away from him. On the other hand,we don't know all that much about how Kovu was
exactly growing up,but since he's not really scarred or anything,I doubt it could have been tragic to that extent as some people think it was.
-Simba is stronger,you can't compare him to Kovu. Why else would Kovu had been planning an ambush attack instead of a straight up fight. As for wisdom,Kovu isn't as wise as you make him out to be,in my opinion. He doesn't have the life experience that Simba has. He spent his whole life in training,while Simba has been in so many different situations that have taught him a lot about life. A fair example of that is when Kovu is more willing to run away with Kiara rather than help the two prides to get along.
-Kovu might be prince,but who made him prince.

-Yeah,as for manes,it's all up to personal preference. I think Mufasa had the most awesome mane