This is a very interesting discussion. It reminds me of an episode of
24. The President was suffering from a bomb blast and the joint chiefs had to decide if the Vice President would take over or not.

[quote="TheLionPrince"]She was the only blood heir of the king and the only person trained to rule, so she'd had to take the crown whether she liked it or not.[/quote]
There is a good chance that Scar didn't have the proper training to become King, though he did anyway given the circumstances. It's true that it's never stated in the movie, but pretty much all Taka fanfiction says that Adahi gave Mufasa the teachings of the Circle of Life and not him. It would also explain his allowing of the hyenas to eat whatever they desired, he simply did not know the limits.
[quote="TheLionPrince"]But if it came down to her threatning to leave if they tried to make her, I believe Simba would've trained Kovu into a ruler and given the crown to him if Kovu wanted it.[/quote]
I would assume this is what really happened.
[quote="WhiteFang"] SP suggests otherwise only through Zira who apparently thought Simba was never the rightful king.[/quote]
Keep in mind that not all of Zira's lights are on upstairs. She could be delusional. Scar may never have said that. She may not have even met Scar...

[quote="MheetusMate"]Kovu will not have as many powers as her. Although in a book of TLK it states that a female cannot rule (which is pure BS)[/quote]A Disney book really said that?!?
Which one? 
[quote="MheetusMate"]Maybe Simba and Nala would simply... mate again :B[/quote]This is the first thing that popped into my mind. Why couldn't Nala and Simba have another?

Speaking of which, why is only one cub born each time a character gives birth? Simba and Kiara were born solo, while Kovu/Nuka/Vitani all look different ages. Most lionesses give birth to
between two and five cubs at one time.