We've hinted at it (and I think mentioned it outright at least once) but yes, NanoBSD will be on the way out. It was good at the time, but the limitations it imposes are really not needed these days. The added complexity of dealing with its wasted space, extra partitions, ro/rw switch timing, etc, are all things we'd be better off without. SSD prices are down, and quality is vastly increased, and worrying about writes is not something many people have to do these days.
Plus a full install with /var and /tmp in RAM would not have that many more writes than NanoBSD (for the base system anyhow…)