I'm not sure why this works on my computer (10.1, SP1... it's probably a bug), but it's worth a shot:
Un-check the "Rotate Marker Symbols with Data Frame" option in the "Data Frame" tab of the window that comes up when you run the AdvancedArcMapSettings.exe tool (found in C:\Program Files (x86)\ArcGIS\Desktop10.1\Utilities). For some reason, on my computer the point marker symbols only rotate with the data frame when that option is un-checked, and line marker symbols only rotate with the data frame when that option is checked. Weird, eh? Rotating symbols with data frames supposedly only works if you set symbol rotation using the "Rotate Points by Angle in this field" option in the Symbology/Advanced/Rotation... window, so I chose the field "<expression>", and put the value 0 as the expression. If you have another version of ArcGIS, maybe all you have to do is check the "Rotate Marker Symbols with Data Frame" rather than un-check it like I had to do.
I don't blame you for not wanting to write df1.rotation values to a Feature Class every time you rotate a data frame... that would make map automation rather inefficient!
Good luck,
Kerry