Also, difficult to see much improvement in propulsive efficiency vs. a high bypass turbofan. Thanks to years of development, plus the effects of the inlet plus the fan exit guide vanes, the 'fan' portions of modern turbofans are over 90% efficient.
Noise might be a big carrot - especially for some sort of unducted fan application - getting rid of that big, heavy fan cowl would be nice - but the previous generation of unducted fans were horribly noisy.