Interesting your read of your experiences.
My long haul travelling pattern is distinctly at the short end of the spectrum these days, 6- 8 hours and I find it very difficult to rationalise the value of F over the excellent J classes available.
I’m not particularly concerned about exclusivity ( a major F differentiator) or food/wine (I often sleep for long perionds), but the seat and sleeping comfort is vital.
Jet, BA NCW, EK (on the 777-300ER) etc are very comfortable. I also find it easy to sleep on the angled beds, e.g. LH.
Unless this new BA seat has hidden virtues, it may well hasten the end of F in the airline.