You and me both
Yes - it would be an interesting subject right enough.
As for open-rotor looking feasible, that's something I've been pondering since the A320/B737 re-engining got going.
Despite the success of IAE and despite Airbus urging IAE to come with a new engine, RR didn't play. Is that because RR felt the GTF was a blind alley? If the open-rotor has made good progress then RR's stance would be a reasonable one, perhaps.
Of course, it may just be that RR isn't convinced by re-engining programmes, perhaps in the wake of the A340-500/600. Certainly, doing the engine and airframe hand-in-hand is always going to come up with a more optimal solution.
I am sorry that this post provides nothing specific.