Not a bit. For getting the same profile no matter the tool angle there's nothing better than a sphere; come to think of it, there's nothing else. I was just taking a guess.
Good!
Yes, you're probably right, with one big caveat.
But emphasize that where concede it's your opinion. If someone else likes the look of big fillets and prioritizes them over performance, it's not for any of use to say they're putting "too much" emphasis on it.
Also, I bet there is no single optimum, even disregarding aesthetics. I read of a study long ago by the MIT rocket society of the fillet size that gives the lowest drag, and I was very surprised by how small that is. I just bet it's so small that the strength of the joint is increased substantially by some further increase (though I can't prove it). And what is "substantial" is another matter of opinion, as it's undoubtedly a case of diminishing returns. So if you've got hard landings to consider, you likely get into a trade-off between strength on one hand and flight performance on the other. And for that, if I'm right, there is no well defined figure of merit that can be maximized because the optimum compromise is, once again, a matter of opinion and preference.
Sorry, that drifted a long way from "ball on a stick".