In the 50s and early 60s Gibson was using nylon nuts. All done well and having the slippery gualities that nylon gives.
When they switched to molded plastic and corian nuts QC went into the toilet.
70s Norlin Era guitars were considered some of the worst. However, there are a lot of great guitars from that era. Because they have been worked on and dialed in.
Technically nut height should be the height if you put a capo on the first fret.
In other words if you fret the first fret, then look at the space between the string and the second fret, THAT would be your ideal nut height.
Also with regards to the d and the g string, you have the greatest angles. (Multiple) The string bends down as well as to the side.
The big G gets sloppy. They don't cut the slots wide enough, nor angle them back enough and generally cut them too high.
An improperly cut nut can cause intoation issues. If the break angle is too shallow, the string may not start to vibrate in the right spot. If cut too high, you have to press down too much making the first few fretted notes a bit sharp.
Floyd rose nuts are the worst. Very little break angle, and then you have those metal clamps crushing the string. A lot of people tighten them too much, crushing the string windings, and wreaking all kinds of havoc on their intonation.
Nothing the matter with corian, it's a stable, hard and consistent material for nuts. It's also dirt cheap. Cutoffs from a counter top can make a shitload of nuts from a material that would otherwise be thrown away.
The problem is how it's cut, thats all.