If you could've writen one scene into the film...

[Eli_Ayase]

I would've added more of Scar's ruling the Pridelands.

[PrincessKiara]

I would have loved to see more of Simba and Nalas adventures as cubs, or even them playing with other cubs in the pride.

As many others have mentioned, I too would LOVE to see even a tiny bit of Mufasam Scar, Sarabi and Sarafinas cubhood.

[Jiirani]

I would like to have seen some form of flashback that Scar had about what made him hate Mufasa as much as he did, or just a important scene from his cubhood, maybe featuring his parents. That would be pretty cool...

[PrincessKiara]

^ I agree, that would have been really interesting and would have explained a lot about Scars character.

[SweetNala]

I would want Sarafina to have more than one line, and maybe a name mentioned in the movie

[WindAnnWise]

I have several:

More of Simba and Nala as cubs.
Mufasa and Scar's background.
More of Scar's reign.
(Would like the second 2 more!)

[cleargreenwater]

Yeah, a little more of Scar's reign would've been good, would have built stakes higher and yet not altered any of the movie's "less is more" perfection.

I personally cringe when I see people wanting to see Scar's childhood.

[Ozy]

I would like to have seen some form of flashback that Scar had about what made him hate Mufasa as much as he did, or just a important scene from his cubhood, maybe featuring his parents. That would be pretty cool...

Yeah I kind of agree on this as well. I think it would add a little more depth into Scar's character and make the story a little more complex. I like when each character has a little bit of good in their bad or bad in their good. It draws me into the story a bit more if I have an emotional connection with both characters.

That said, that idea may not work that well when it comes to trying to give kids a specific right and wrong character.

[Pocahontas]

I would like to have seen more of Kopa.

He doesn't exist in the first place in the movie though. The cub at the end, according to Disney cannon, is Kiara.

Shadowland would be a bit much though, don't you think? A silent, mournful song, slow paced, the kids would squirm.

More Pumbaa and Timon!

[PrincessKiara]

I would want Sarafina to have more than one line, and maybe a name mentioned in the movie

That would have been nice. I`ve read how the Bath Scene was originally going to be longer (with more lines from everybody, including Sarafina) but as the work on the scene progressed, all of Sarafinas lines were cut, and she was left with her lame: "What do you think, Sarabi?"
Still, better to give her one line than to make her a speechless character. I do wish her name would have been mentioned though, it might make people more aware of her. She is Nalas mother, after all.