Is it a players off season improvements (or losses) still primarily affected by their work ethic? And is there a level where you can expect to see certain amounts? Such as a 40-49 WE will be 0-10 points of improvement, 50-59 is 10-15 points, etc? Or is that just all random?

Just trying to make sense on one of my players with 43 WE who only went up 3 points in the off season, even with very high or high in quite a few categories.

yes WE does impact off season improvements

To add to this, you usually want a WE of 30+ to see offseason improvements. From my experience a WE of 20-30 will usually not move much, and anything below 20 will be a net loss. Of course, there are other factors such as potential (low, high, very high, etc), and I believe stamina usually decreases in the offseason for most players.

Does practice time from the year before have any effect? Or is it all random?