Well, depends on what you mean by unproven, could you provide an example?
Uncharted was unproven when this gen. began. I bought the game on the first day simply because I had played the demo a week earlier and knew it would be massive. The same applies for Lost Odyssey. It was a new, unproven, IP. However, simply looking at screen shots, reading about it, and knowing that it was made by Mistwalker was enough to warrant the first day buy.







