It will be interesting to see if anyone does actually does take the next 'quantum leap' in business class seats within the next 10 years. If they don't (and no-one here seems to have any ideas, so does anyone anywhere really have a clue what that might be?) then BA will for a good while have the latest and greatest version of a seat type others have tried and tested for them and in some cases got wrong (Finnair). It doesn't seem anyone else will go down the Q-Suite route due to it's economics so BA will have a whole fleet full of pretty much the best seat out there. The only improvement I've actually heard is on its way would be to for the IFE (remembering past selections, device connectivity, 4K etc, and maybe in seat climate control) but that is all stuff BA could easily evolve this seat to have as well if it becomes a selling point for others.
Also, the fact they have gone for a customisation of a standard product will make it easier to shift to another customisation of another standard product in the future. I'm sure the shift from "we must do it in-house' mentality delayed this project, now they have got over that mentality they can spend their effort building relationships with manufacturers to get the best possible outcome for future evolution of this seat and/or a replacement rather than trying to reinvent the wheel themselves.