AbigailII:
you cannot see it's beneficial for the trailing player that draws won't count?

I think that's a valid point - that's actually how it works without the doubling cube, too. In my defence, I'll say that I covered this possibility when I said that I didn't see any serious drawbacks. Let's take your argument a step further:

If I'm trailing in a match, and the current game is likely to be a draw, there shouldn't be any hesitation to double if that means the game effectively won't count, should there?

Why is that a problem? Most likely, the game is going to end in a draw. In that case, both you and your opponent gets the double of 0, which is 0. So you can double, but it will only have consequences if there are indeed other possible outcomes than a draw. Which I guess was sort of the intention of introducing the doubling cube in the first place. Or, in other words: If there is even the slightest possibilty that you might lose, there should also be a slight hesitation to double. And if there's really no such possibility, then as you say, there shouldn't be any hesitation. I think that is how it should be. I don't see a problem.