Keeping track of two separate undo lists seems cumbersome and unnecessary. It would get confusing faster than you realize.
Not really: Given the complexities of the CAD software and other 3D tools many of us use daily, having and operating two independent undo-redo stacks isn't going to be too challenging.
Also, since there is already a checkbox for including camera movements in the undo-redo stack, that same checkbox could easily be extended to allow users to opt out of a separate stack if an individual felt overwhelmed by that extra undo-redo path.
For the rest who are accustomed to operating heavy machinery, so to speak, it would be a huge benefit - and one that, for good reason, users have been requesting since 2014.