Hi Tom,
This is the number one enhancement that is on my list but I'm not quite ready to start on it. It will be a great feature but it touches nearly 50% of the software code and will require a significant investment in programming fees. The concept is simple, but it is a dramatic change in how the various row types are drawn today. Since it changes the underlying data structure, it changes all the Views, the user interface, the file storage routines, printouts, etc. You are not the first person to have requested this, though, and I would certainly use it myself.
There is a way to do zero rotation today, though. You can change a row's height from whatever it is to zero so it will no longer be visible. The row above it will now appear to have a zero rotation. A good way to experiment with this is to add a bunch of rows to a test vessel and the select every other row with Ctrl-clicks and then change the row height to zero.
I'm hopeful I can start on the actual enhancement later this year.
Lloyd