Valiant definitely hasn't, my late June cruise was around 700 sailors and the previous ones had had fewer. The first July cruise was over 1,000 but still below 50% (which would be ~1,300-1,400). My experience was this was good in some ways, especially because you could book everything, but meant some of the side events didn't go ahead due to lack of demand and a couple of the events would have benefited from a bigger crowd to build more atmosphere.
We asked at Sailor Services after boarding if we could move to D13 from D14 and if possible to a room closer to the middle of the boat. They did this without charging so we effectively got a $50 upgrade from Sea Terrace to Central Sea Terrace. People were arranging upgrades to better rooms but I'm pretty certain all, or virtually all of these, included some form of payment. You need to factor in that Virgin's ships have a LOT of Sea Terrace/Central Sea Terrace rooms but relatively few rooms above that, a lot of premium rooms are booked by people who got lots of credit for previous cancellations, and a lot of the remainder are taken by people who will have big for an upgrade before setting sail.