First off, I think it was really cool to see an alternate version of the song. I always like seeing that with any animated film, seeing how it's progressed from its earliest stages to its final presentation.
I prefer the film version of the song over this, and I'll tell you why--it's more cohesive. As stated, the qualms with this version of the song included that the original did not fit in with the African themes of the movie, and I can certainly see that. And that's the issue that exists here, aside from the fact that it's a rough demo (though they do that with most animated films). If you've got a movie, the music of which is largely vested in African traditions, squeezing in a pop song from the other side of the spectrum isn't going to flow well. It's almost like if you were a band creating a rock opera and you suddenly added in a country-western song. Or when they decided to do this:
http://www.youtube.com/watch?v=BxHNztg0X3s in that strange Titanic animated movie. No matter what the quality of the song might be, it's still going to stick out--and not necessarily in a good way.
I still do like the feel of this version though. Lyrically it's a bit cheesy, but it IS a love song, after all. And from the storyboards, it doesn't seem like too much changed animation-wise, at least from a general standpoint. Cool little find; I like finding these sort of things from the earlier stages of a film's progression.