From a purely financial business point of view, if Nintendo was to go with early spaceworld type graphics it would make them a fortune especially if they already had a demo for e3.
Reason is, wind they 1st showed the demo everyone fell in love, then we saw C el link, so many were shocked and angry, then we adjusted and learned to love cartoon link , especially after seeing video of him in motion. This cause a huge stir across the internet when it happened, it would cause an even bigger one if they went back to the demo footage style for the next game in the series.
Not sure about all of you but I'd pick up both versions for sure, and many many others would pick up the latter of the two for sure.
Would be a cheap and very effective marketing plan on Nintendo's part to do it the way they did, if the 1st Zelda release was what we saw at spaceworld then the buzz would be good but not as blown out of proportion as it is now about windwaker. Free advertising for Nintendo, they seem to have a great way to pull things like that off.