In my opinion (for what it is worth) an effective cure for type 2 diabetes would have to eliminate insulin resistance whilst there are still enough beta cells to handle any glycemic load up to an OGTT. Fasting and post meal BG levels should be in the normal range, as should the HbA1c, without any major dietary constraints.
This would, of course, recognise that you have a metabolic vulnerability which led you to develop T2 in the first place and thus it could return if you abuse your system repeatedly.
I see that some people would require a return to full functionality of the pancreas. I would consider it a cure if the pancreas still had enough functionality to last out the rest of my life. Everything wears out eventually so if my pancreas was in line with everything else (apart from my knees) I would consider that effectively a cure; or so close not to be worth arguing about.
I believe a 'cure; to be possible if caught early enough. Insulin resistance/metabolic syndrome appears to be caused by visceral fat around the pancreas and liver, though there are of course other causes too.
In early stages, the metabolism of carbs is hindered but damage to the pancreas is small. If the visceral fat is removed through diet and the metabolism is increased/improved through exercise the cause of the problem is removed and the condition may be regarded as cured.
If all BG readings are well within the normal range whatever food is eaten, and without any medication being taken I believe that 'cure' is an appropriate definition. If the low BG is due to a very low carb diet, this cannot be seen as a cure, though it may be just as effective in preventing complications.
I haven't had a FBG over 4.5 in over 6 months, and my last HbA1c was 31 despite averaging 180g/day of carbs. Sure, if I put weight on again the problem may return, but if I hit my arm with a hammer my broken arm may return. For now I have no intention of stopping testing as I may be wrong.
It is of course the case that for many people, damage to the pancreas is too severe by diagnosis for this approach to be feasible. In which case, eliminating carbs may be the answer.
I tend to go along with these types of views. And it does happen for some people.
To avoid arguing over words, I'll just say that if that ever happened to me, I'd be so happy I wouldn't care whether people called it "cure", "remission" or "dfasjhhfsd".