I guess the redesign is due the terrible experiences of the rotating engines on the V-22. After so many fatalities they reduced the vulnerability of the engine to ground-strikes but the lack of ground clearance is still a concern to operators and the jet efflux is less than ideal too. This design (if it works) looks much more appropriate for an aircraft you plan to land in the dark, on uneven terrain in a threat environment.
The internal bomb-bay looks interesting.