So I've noticed some fundamental differences between the features that WERE available under the "Add Arrowheads" feature, and the ability to add arrowheads that is now included in the Stroke panel. Insofar as I understand, there was not a way to customize arrowheads under the old "Add Arrowheads" feature; you were limited to the options preset in Illustrator (please correct me if I'm wrong). With the arrowheads under the Stroke panel, I can now customize arrowheads easily and add my own. However, when files are backsaved or opened in more recent versions with the old "Add Arrowheads" feature, they remain "live" so to speak- I can adjust their scale and change arrowheads easily in Appearances-->Add Arrowheads. When I backsave an arrowhead in CS6 down to, say, CS4 or CS3, it "breaks" it- becomes a featureless stroke with an overlapping, arrowhead-shaped path at the end of it. In order to change the arrowhead, I have to remove this path, re-add the arrowhead using the Stroke panel, adjust the length of the stroke again, adjust the scale again, etc.
I'm assuming this is because the Stroke version of adding arrowheads wasn't available in these previous versions of Illustrator, but is there a way to somehow trick Illustrator into keeping these arrowheads "live" so that I can adjust them simply even if they're backsaved? Alternatively, is there a way to access the old Add Arrowheads option and customize it without having something from an older file handy?