A few things based on 50+ rounds there:
1. The longer par 4's like 6, 8, 9, 13, and 16 obviously play far shorter than they used to. That makes a huge difference.
2. In February, the course is soft and the rough is short. During the 2018 US Amateur, with firm greens and serious rough, it played almost exactly as much over par as Pebble Beach did (about +4.3).
3. The course has been made easier since not long after it opened, continuing through the present. There's more grass, more formalized bunkers where there used to be dunes on 1-5, no iceplant, and so on. It's a resort course, and while I don't want to say it's dumbed down (because it's still an
awesome course with great greens!), it's not
just equipment that's changed since 1966.
4. Should they choose, there is room to move back tees on 7, 8, 9, 11, 12, 14, 15, and 16. Some would require a bit of construction, but the room is there.
5. As a side note, the 17th green was reconstructed over the summer (pic below), partially for maintenance and partially because most of it was unpinnable due to slope/speed. I've heard that #8 might be next, because the front half of that green is unusable, and the front half of #9 is barely usable as well.