Personally, i think its a great idea, because, as mentioned, it gives the consumer options, 10 quid for a game ur not sure about would definately convince me to at least try it, anf hey, if I like it then yeah I'll upgrade, IF its a game I want to play online, or I need to because of DRM crap, providing the upgrade doesnt push the price over the full game price we pay now. I'd love to see this model introduced in the west as I see it stimulating the games market by helping "chuck" make the most of his disposable income.
Lets face it, I know the I personally, and probably many others, hate when u buy a game for £40 odd and it turns out to be shit and sits on the shelf unplayed, it feels like a waste of money.