With the understanding that I don't find Kiara to be a particularly sympathetic character it might be unsurprising that I lean towards CYFTLT though I think I have less biased reasons then simply my views towards Kiara.
CYFTLT is to me, not just about the love between Nala and Simba but the peace that being in one and others company brings. We all know that at this stage in the movie Simba's haunted as all heck by his past and really doesn't feel he has a home anywhere, consider this line, that isn't in Elton's full-length version.
[quote]It's enough for this restless wanderer - Just to be with you[/quote]
Elton's version talks about warriors but in the movie it's a wanderer and it's very much saying something about Simba finding not just home but a place where he thinks he belongs with Nala, recapturing that sense of home that he lost upon Mufasa's death. Simba's night with Nala isn't just about the fun sexy times, in my eyes at least. On Nala's end there's less that can be said for sure since we have little to no cannon on what happened with her when Scar was in charge, certainly there's a sense that here's someone from a happier time that could right everything. What's perhaps more telling is the strength of he belief in Simba in spite of those long years. This is explicitly shown:
[quote]Why won't he be the king I know he is?
The king I see inside?[/quote]
but also after the argument and after Simba's kept up all night with Rafiki she's still searching him out, clearly she doesn't believe that 'just dissapointed' is going to be her last words to Simba. This is actually part of where I think the movie could have been better in another way, Rafiki & Mufasa Storm certainly worked but I think having Simba and Nala work it out together would have made both stronger characters.
In short, CYFTLT is all about the huge mountain of subtext going into that scene, there's so much of it that the movie more or less pivots right around that point.
LWFAW strikes me as very nice and romantic but also failing to really get at the meat of any of the problems in the movie. It's not like Kiara and Kovu's relationship is a new thing, the subtext leading to that song just seems to want to launch them right out of the movie/pridelands instead of drawing them back towards the ultimate climax. Nothing in the song leads to the answer Kiara gives shortly after that actually resolves the plot [quote]we belong with our pride'[/quote] and even that statement has some massive 'have you seen my family' holes in it from Kovu's perspective.