Generally, I think open sourcing user frontends to propriatary channels is a great idea. I am only not so sure if it is the best for desura.
Steam is seeing a lot of hacks for their clients targeting to decrypt games you do not actually own. With desura, not applying that harsh sort of DRM, I think it will be very easy to hack the client to throw out stuff for free.
And dont tell me "Nah, the indie folks are not like that" considering the abuse the last HIBs got although they are almost giving the games away for free.
I hope this is the right choice and I would hate to see such a friendly move being ultimately turned into the demise of the desura platform.