Ico had just that (in Japan and Europe that is) but I don't know if it helped much. The sales were simillar as for the US version, even a bit less I think.
On principle I agree with you though. I'd like to see something like LE version of Ico packaging.
If that doesn't happen, at least for once, the US gets slightly better box art.
You really don't need to have beaten ICO to thoroughly enjoy SoTC, the game stands on it's own. There are some elements in the game however that ties to ICO, and some in the story, so you'd be losing out on those moments ...
I think the boxarts are trying to be different between all the countries...As a matter of fact, all the boxarts look like they were taken from a different screen....