Good points about the writable user shares being a "nice have" only.
To me, must have would be:
1. Security, for home users would be nice, but this is stopping me from recommending an unRaid server at my work, I am in charge of IT but it would have to be secure, at the user level.
2. S3 to save power and hence dollars, and the enviro. Plus the server will last longer.
3. Shorter drive spin down times, preferably drive specific.