I just gotta chime in here. Didn't play GT until 5 so there's nothing "nostalgic" about Grand Valley for me. Since the term valley seems loosely interpreted in the name, I suspect, since the layout is generally similar to previous versions of the track, they tacked the Grand Valley name to it. After all, Grand Gulch, Grand Gully & Grand Ravine just don't seem to have the same punch as Grand Valley, and Grand Canyon is taken.
Haven't driven it yet, am about to as soon as I finish this post, but it does appear, after watching a few of the videos posted, to have some valley like areas that could grow a decent crop of whisky. If there weren't then I would be unable to call it Valley, Grand or otherwise.