Curves Adjustment Line and Point Size

'Anyone else find the new curves adjustment line and points to be overly thick and huge?'
Yes, I see that here on Windows.

'...previous width and size of the line and curve points were just fine and easier to make small adjustments.'
Whilst I prefer the previous thin line curve display, I don't find any difference in the ability to make small adjustments. Both input and output step in increments of 1 whether using the mouse or the keyboard arrow keys.

Dave

There is no built-in Photoshop option to change the thickness of the curves line or points.

You could try resetting preferences or updating your graphics card. You could also try Preferences > Performance and take the check on or off of Graphics Card.