Having watched the video on the first page of the original GVS and through the various games a few things stood out. Firstly, wow, the jump in quality to GT3 really was something wasn't it? That game looks great even today.
Anyway, more on topic, GVS wasn't really a very scenic location to be honest, off track was actually quite bland. Not a bad thing as such, certainly realistic enough in terms of race tracks, but what we have now is a lot nicer to drive around in that respect.
Also, my initial perception from screenshots was that the layout was very similar, they'd just inverted some of the elevation changes, i.e. a corner / straight now goes downhill instead of uphill as before.
Watching the laps of the old circuits, this is even more true than I thought. Also, lapping the new Grand Valley, I felt the 'feel' of the circuit, as in how you approach corners etc. felt very similar, especially from start line to the tight hairpin. Looking at that video, the actual racing line through the corners looks like it would be very, very close all the way up to where the blue bridge would have been.
I think other than elevation, the track is actually closer in layout and ultimately, approach in terms of racing line than it seems.
I also think the new chicane after the blue bridge is better than the old one between the stone walls, and the little section after that is more interesting and the final corner again 'feels' the same in terms of almost flat out not quite don't run wide etc.
So I think in conclusion, not only am I a fan of the new track, I actually think it's better than the old one, having watched the laps of the originals and done a bunch around the new one!