This all makes me wonder if MusicXML has reached its use-by date, or needs a major overhaul in order to allow more complete portability of musical notation data between programs.
Also, there have been significant developments in Sibelius at least over the last few years, I’ve had about 5 releases so far this year alone. But anyway, yes Dorico has introduced some features that really stand out in the field. I just hope the structure of the program can cope with what is being asked of it and that addition of rule options for things affecting layout don’t bog down the program too much.
The people I know who use notation are all keenly aware of Dorico and either use it already or are just waiting on a couple of things to move to it. With this I think will come the publishing houses.