I observed the same issue when drawing in most drawing/painting applications that are bitmap based (sometimes even vector based). There is a simple reason for the jaggies: when you draw zoomed out the software has to interpolate the screen/wacom coordinates with the zoomed out version, which may result in less optimal lines.
In my case I use an older Intuos 1 tablet with three screens - with a screen setup of 2x2540 pixels and 25% zoom, approximately 1 tablet point per screen pixel is available. And that causes frazzles when working zoomed out.
I did notice Lazy Nezumi caused the frazzles to look worse, because the lines are so nicely drawn, and the frazzles stand out more.
Solutions for me were mapping the tablet during drawing to one screen only, and making the switch to Manga Studio 5 (Clip Studio) for my line art. Manga studio has much better interpolation than any of the other drawing software I have tried (and I tested this in Photoshop, Photoline, ArtRage, and some others).
Even with the tablet mapped to one screen only, I found that Photoshop still adds some frazzles to the lines I draw when zoomed out. In Manga Studio those are either not present, or much less pronounced.
Another solution is to draw with vector brushes, rather than bitmap based ones. The vector brushes will look much nicer, and we can work resolution-independent. Obviously, this will not work in Photoshop - again, Clip Studio to the rescue, because luckily enough that software DOES support real vector-based lines.
The drawing feel in Clip Studio blows Photoshop out of the water as it is, so I would recommend to do your line art in Clip Studio, and then perhaps export to the required resolution into Photoshop for colouring/painting. It’s really worth for the line quality alone. I am not alone in this, btw - many artists have made the switch to Clip Studio lately because of the incredible line quality and drawing feel.
http://www.clipstudio.net/en/
