I think the main reason why fishing was canned in WW was that the water was opaque. However, there was a demo included on the disc that had clear water, so if the next game doesn't center around water so much, then the GC should be able to handle the clear effects. It's been stated that Link will look different, so I guess smaller changes to the engine aren't out of the question. I wouldn't be supprised if the fishing returned.