A couple things I'm noticing in the comparison. I still hate how GTS and GT7 don't shift accurately. The early throttle application is ridiculous. It's definitely not realistic on an automated manual and it's very poor technique on a manual transmission. GT6 didn't make that mistake and they really need to fix it, it's obnoxious and degrades the immersion.
Also, I'm not a huge fan of how the new Deep Forest is...less forested. One of my favorite aspects of the classic track were the trees genuinely overhanging the track and the dark tunnels that felt you were really driving through a forest. That's the whole point of this track, right? But looks like they've cut back the brush quite a bit in the name of safety and now the track is much more open in the hills, with brighter tunnels and a less dense feel which I think goes against the whole purpose of the track. I'm sure I'll love it, and I do actually like the fact that they've changed the layout slightly, but I wish they kept the deep, dark forested feel.
I also recall the view of the cliff/valley off to the left of the uphill section being very iconic. Weirdly while the new one has lost some forestry elsewhere, this uphill section feels more forested, while the old one had the giant canyon to the left which always made me feel slightly uncomfortable. It was actually distracting from the track itself which is part of why the track's scenery was so iconic. I wish they'd have kept that precarious cliff view.