[quote="TheLionPrince"]Simba's reign was faced with a difficult crisis while Mufasa's reign was more easier and didn't have major conflicts as far as the movies show.[/quote]
Like I told DGFone, I'm pretty sure you're doing that backwards. Mufasa's reign appeared "peaceful" in the movies because he was strong and respected enough as a king to keep everything from going awry (until his brother double-crossed him; which brings up another unfair comparison between Scar and Kovu, but I'll come back to that in a minute). You seem to be judging this from the assumption that Mufasa only looks like a strong ruler because nothing bad is going on, when in reality, the hyenas are constantly breaking into the land and trying to gain territory into the Pridelands, and only the fact that Mufasa's a tank in lion form keeps them from succeeding.
In my opinion, this puts Mufasa's job FAR beyond the "feud" Simba had to worry about. Until the final moment, Zira was an entirely passive entity. The only thing Simba actually had to deal with was paranoia (which I suppose you could argue is worse in some ways).
As for Simba's skepticism of Kovu making his judgement superior to Mufasa's judgement of Scar (not your idea, but I remember someone bringing it up), I'm going to call BS for one reason only. Scar was Mufasa's brother. Yeah, he was shady and detached from the rest of the pride, but Mufasa had no proof that Scar was doing anything wrong, and he honestly wanted to trust in him. He couldn't throw his own brother out of the pride just because he didn't like to interact with anyone.
Kovu, on the other hand, was a known member of Zira's coalition, so skepticism of the validity of his story that he'd "left" was natural. It was common sense; nothing to be praised over, really.
So yeah. Obviously, I still feel Mufasa's the clear choice, but whatever. Everyone's entitled to their own opinions.