(The "yes" in the first paragraph is directed towards Dabi, not Duke 2.0. Good thing I caught this before posting, eh?)
Yes. I can understand accepting donations to support further development, provided you don't just pack the money in a suitcase and run, because it's voluntary and there's less of a promise to the consumer involved.
Charging someone so that they can have a product that doesn't exist yet has always seemed a little fishy to me; the consumer should, at least in theory, know what he's getting before he buys it. There are a thousand and one awful things can happen during the development of a game that can sidetrack it, delay it, or cause it to be something other than what was initially planned (to some degree). I'm not saying that it's likely in this case, but it's certainly a possibility, because the people are paying for something without any promise of what that something will actually be, a promise that should basically be intrinsic to all purchases a person makes (unless there's some element of gambling involved).
I would say more, but hat is the point of this? That we are idiots for trusting that something will come?
Well... what's the point? Is there actually a point to paying for something before it exists, rather than waiting?