The "Kingdom Hearts theme"

So Kingdom Hearts has that reoccurring song "Simple and Clean" by Utada Hikaru. They play it in the credits in many of the games, in the opening cutscene, etc. After finally playing Birth By Sleep I just realized that the lyrics really have no relation to anything in the KH series. Was there something lost in the translation or something? I know the original song is in Japanese, but I don't understand Japanese so yeah..

 

I believe that Passion and Sanctuary were written by Utada with Kingdom Hearts in mind. I remember reading that one of her major sources of inspiration was thinking of time passing between three friends, how they've grown up and their relationships/interactions/lives have changed.

I'm not sure whether Hikari was written with knowledge of Kingdom Hearts. Either way, it's important to note that neither songs are direct translations--lyrically, they're essentially different songs. The translated lyrics to Hikari do share themes with Kingdom Hearts (destiny, light/dark, the future, awakening):

( These, as compared with the lyrics to Simple & Clean, which I'm sure we all know by heart now )
( Translation Source )

Point being, Hikari does fit in, in my opinion. When Kingdom Hearts was being released worldwide, however, Utada essentially had to write new lyrics that fit in with the musical structure of Hikari, which is an incredibly difficult process and was cited as one of her reasons for not renewing her contract with Disney.

Personally I don't feel the lyrics to Simple & Clean are too out of place, but of the four songs, they probably fit the least. Both Simple & Clean and Hikari, in my mind, deal with moving from one phase of life to the other. Looking at Hikari through the lens of Kingdom Hearts, it seems to be Sora...

You think ahead too much.
Stop such a meaningless behavior.
I'll eat a delicious dish today.
We have a long future ahead of us.
I don't know what becomes, either.

Don't finish it.
Revise it more.
You should just film the scenes one by one.​

... who isn't really too concerned about the future, he likes just chilling on the islands and having his little adventures. Riku, however, has his head within the clouds, always looking to the future and wondering what's out there. He wants to seize life and figure everything out, and is seemingly slipping away from Sora for that reason.

Simple & Clean presents similar themes, I feel ("when you walk away / you don't hear me say / please oh baby don't go" = Riku symbolically 'walking away' from Sora).