I like your idea of using Inkscape as the engine, I hadn't even thought of whether it had an api that would let me get at things. I have a perl script (mostly because I learned perl in 1991 before python existed and have tended to stay with what I know best) that will move the style commands that Inkscape likes to use, but that break bendable leads in to plain xml and removes the px (that also break fritzing) from the font commands. Doing that within Inkscape would be a lot more convenient. However (it sounds unlike you ) I'm not really a developer, I spent 20+ years as a network engineer/ security officer/ system administrator of last resort rather than developing (and started life as a hardware type ). I completely agree a script it is the best answer to fixing up the parts, as you note it can fix what is obvious and flag that which is broken but not obvious how to fix for human attention which should cut down the work load substantially. To be fair to the Inkscape developers, neither Old_Grey or I are Fritzing developers we so far haven't heard anything of them ...
Peter Van Epp