I think Rick Barnes would pretty comfortably land at about a 5 on that coaching scale, not to jump down into more examples though. That said, there are as many examples of high level success under a great coach with meh recruiting as there are of the opposite. There's not really a right answer there. The challenge is to find someone who is balanced and strong in both areas.
Personally, my biggest frustration with Groce has been squandering of talented kids, so that's why I'd rather have a coach who gets the most out of their guys. I think coaching also provides a more solid floor than a dependency on talent to overcome coaching deficiencies does, because coaching ability is far less fluid than recruiting.
That said, a lot of this is a largely subjective/philosophical dispute, as you referenced. (You could certainly quantify and generate correlations here, but I'm not paid to do that, so I'm not going to take the time go that deep into it). There is certainly a minimum talent level you need to really be successful in the P5, though. I think the point being made is it really isn't that hard to get the talent necessary to be a tournament team at Illinois.
Yep. I agree.
I hope you also agree that making the tournament may be a goal initially, but I want Final Fours and championships. We're sitting here with this shiny Ferrari, now we just need to find a guy that can drive it.