Like cugila, I'm a bit confused as to why this is even a debate. It's not a theory or a postulation, it's a simple process of chemical reactions that DOES happen in the human body.
jopar, you say that "in practice it tends not to work very well". It works PERFECTLY in practice; i.e. it does exactly what it's meant to do. In my opinion it's important for low-carbers to know about it as it does affect blood glucose on a low-carb diet, but I don't think anyone is trying to make out it's some magical process that will stabilise your blood sugars perfectly and will mean you never go hypo. Likewise I don't think anyone is suggesting eating protein to treat hypos instead of fast-acting carbs. And as you say, if you eat enough carbs then the effect is so minimal as to be ignored.
That said, gluconeogenesis can provide the body's glucose requirements - as shown by the poeple who eat VLCD or zero-carb diets for long periods. In diabetics (particularly T1's) it's impractical because we have imperfect control and may need carbs to bring us out of hypos - but aside from hypo treatment, you could eat zero-carb and have enough glucose to survive and function well. You'd probably run with very depleted glycogen stores which would inhibit moderate-high intensity exercise (though not low intensity or occasional very-high intensity exercise), and it might not be what you want to do - but you could do it.
I eat a low-carb diet which is therefore inevitably high-protein and high-fat, and it does give me good control. I'm not claiming it's a magic bullet though - of course I use different insulins (2 in my case, just a fast and slow acting), and measure frequently, and still have hypos which I treat with dextrose. I'm not trying to pretend protein magically solves all these issues. But it's important for me to take into account the effect of gluconeogenesis as well as the few carbs I eat, because it does affect my blood levels. And eating this way dropped by HbA1c from the 7's to the low-6's in 11 weeks, and my blood glucose is currently averaging 5.7 for the past 3 weeks (predicted A1C of about 5.2).
As an aside, I don't often fuel exercise with carbs either - very-high-intensity exercise will be covered by hepatic glucose release (and actually required a small injection of insulin to prevent a spike), while I'm sufficiently fat-adapted to be comfotable on very long-duration stuff without carbs, I just lower my morning basal does a little. It's only the fairly-intense stuff in the middle that needs fuelling with carbs.
