The only other thing that occurs to me is you have quite diffuse lighting. Which is obviously important for many aspects of benchtop photography. I wonder if experimenting with a spotlight for your head shots to see if more defined shadows and highlights gives an impression of increased sharpness.
Have tried it and people didn't like it. It's also very fiddly to get right.
The last thing you want is to dick around with lighting every time you shoot a video.
Sure I could put up huge studio lights in front of me but they would be a complete PITA and just get in the way every day, believe me, I've tried.
I agree with you.
I've done stage/event lighting, so I see minor stuff that could improve a bit your quality...
But improving your setup would reduce your flexibility, increase your set-up time and cost a bunch (you would need a light mixing table and then faff around with a light-meter)
I really don't think it's worth your effort.
At most, I would put custom contrast curves and fiddle with clarity in your post process. That would make it more pleasing to the eye, but less realistic.
Personally I come here to learn stuff, so I'd rather have somewhat realistic colours and contrast to finding Dave very pretty.
Quite frankly, for you being a confessed "non arty guy", I think your general sense of light, colour and composition is pretty good.
(for example, your skin tones are nice and you don't have a big reflection on your nose)