Welp, after a couple hours of playing I got a DX error (100000d or something to that affect) using just the RegEdit fix I posted.

Locked up and crashed out to the desktop with the DX message. Was hung for maybe 5-6 seconds before I got dumped out.

I have since got it to replicate (though not 100%) using cutscene transitions again.

I've noticed on a great many of the error threads floating around regarding Nvidia cards the vast amount of people who report similar issues are on Win 8 or (much more often) Win 8.1.

Going to clone my current HDD to a back up and install a copy of Win 7 and patch it up and try FFXIV and see if I get similar errors.

TDR started with Vista, so 7 has it as well, but I'm going to start with it set to default and no preventive measures applied and see what I get.

I kind of hope reverting my OS isn't the only reliable fix since others won't have previous copies of Windows lying around. :/

On a side note, I did find a thread where Nvidia acknowledged the error with TDR and their driver, but it seems to have died off in terms of their input.

Some people have said the problem disappears on older drivers, but which driver version exactly I haven't gotten a consensus on.