So it would appear that the inlet duct of a turbofan engine works a lot of magic in reducing shock losses, namely by slowing the flow to subsonic speeds? Ignoring problems with blade balance (since it seems we have come to the conclusion that we do have the technology to get it crazy precise) then, in the case of the UDF, why would we choose to have all the blades hanging outside the duct for what is basically a turboprop wanting to go fast?
I guess the better question is, why can't we use an existing turbofan design and just have all the air exiting the combustion core drive a conventional (ducted) fan?