New cast iron usually isn't finished as well. I have seen people take new cast iron to a machine shop and have the cooking surface smoothed down a bit.
There's apparently something of a trade in antique cast iron; I don't have any, but I've heard it used to be smoother. But even in new stuff there are different qualities; my no-name cheapie is definitely rougher than my Victoria brand pans.
I recently bought a new cast iron skillet and it just doesn’t seem to be of the same quality, it’s a lighter colour and doesn’t seem to season as well. Are there different grades of cast iron, or are they just not made like they used to be?