Having seen the seat map - inclusive of galleys and toilets - I've to say that I'm deeply disappointed. I mean, it's not as if it wasn't going to be anything but what it turned out to be, but I still had some hope.
Basically there's no separate toilets for WT+ customers; they'll have to share them with those in Travellers, for a grand total of 6 bogs for 260 passengers; Club has two or three. There's no cross-galley mid-cabin; unlike most reputable airlines, BA has gone for a configuration with only two galleys, one up top and the other down at the very back. I'm sure that it'll cause joy to no end to those who press a call button in the first row of WT+... And the galleys, compared to those of other airlines, seem to be on the tiny side.
From a "public amenities" point of view, then, BA's A350 feels more French Bee (which I admit has the 359, but hear me out) than Cathay Pacific.