This might have been addressed before, but one thing about TLK SP that has bothered me is that Kovu should have taken a bit longer to turn away from his mission to kill Simba. I always wondered why Zira wouldn't order Vitani or Kovu to kill Kiara as well to wipe out Simba's line to really reclaim Scar's throne. I'm not saying Kovu was inherently evil just that Zira saw him that way and as Scar's heir. He grew up in hatred trained to kill and hate Pridelanders. Vitani wasn't evil either, but she was brainwashed in the same taint. They grew up thinking they were justified. I understand the real reasons this didn't happen was time constraints. I wish Sarabi had been in the film (I know her voice actress passed on) but Kovu could really get a sense of the damage Scar did versus what he'd been told really happened.
I guess I equate it with someone raised in a cult in that it takes a lot of coaxing for them to see the turn behind what they were raised to believe. Kiara would help, but Kovu would have to see that she is not horrible like Zira makes her out to be either.