I’m not sure I get the concept.
Isn’t this just a turboprop variant? Or a non-ducted turbofan?
I don’t see anything truly new here.
Also, if it saved gas and this outweighed the downsides of the design, wouldn’t it have been used for the past 50 years?
I’m not trying to be snarky (for a change ;-), I just don’t see the point.