I think it would help them avoid some common problems if they did have developer documentation prior to the kickstarter launch, that said though it wasn't clear from their page what they were seeking the funding for exactly, and that is where i decided I couldn't participate.
Either the funding is "to develop the platform and make it available for developers to write games" or "to get the platform we've developed into production so that games written for it will have a wide audience."
If its the former then there is a much bigger gamble here, they may not be able to make it compelling enough to actually be a competitive game platform. If its the latter then they should have the 'big' pieces in place software wise and the remainder might be just refinement. Reading their collateral and listening to their pitch I think it is more if A than it is B but I would love to hear differently.
I keep trying to remember the DirectX guy who created a company to make 'game develoment for the masses' and then faded away, damn my aging neurons.