I can't speak of this with absolute authority but I think the widening issue is caused by an AI element of the WB that makes them not able to see the entire map... they reduced the bug by increasing the range from 20 to 25 blocks. The point is if that's what causes them to act weird then don't keep spawning the WB's so far away.
WB AI to me has always seemed fairly predictable, there have been some oddities but never on the scale that seems to get reported here. I made great use of them before the update and make great use of them about the update, there are situations where the old WB was better but I think in general most people will find the WB's less frustrating than they used to.

