I voted snapshots though I must say basic definitions of the features would have helped. The number one improvement everyone should still be asking for is a file explorer than isn't a half ass version of Krusader or Dolphin. It doesn't make sense this far into the project to not have made a good solid GUI based file explorer. Having FOLDER based version is probably all most people need.
It's a server mostly for large cheap storage pools. You want features for data management, exploring data, observing data use, monitoring data changes. You want features for backup and file syncing all built in and if not robust at the very least fairly seamless and fool proof. Snapshot makes sense, expanding arrays/drives makes sense for SOME, but probably less ppl than anything like Version.
The other BIG weakness of unraid is file sharing to insecure windows desktops. I think building basic client folder syncing in makes the most sense, but it all needs a well polished UI. I didn't buy unraid because I wanted to drop to command line or use Krusader. I bought it as an alternative to getting balls deep in Linux apps, command and scripts because that all takes TIME I don't want to spend.
That being the case when it comes time to share a file my natural response is to GET ER DONE and that means a public share or simple SMB password. That's ok, but it could be a lot better in this day and age and it could save untold bits of data from malicious corruption via those super insecure network shares, which are mostly not being used in a direct access fashion anyway.
For all the people that just want to put and pull files from Unraid and browse and delete files from shares it makes good logistical sense as a product and consider the likely customer base to build that feature it.
OR just look at the threads as to what questions come up the most and add features so the problems don't exist. ;) That's the easy way to do things. Solve the most common problems and call it progress, chances are you've done more good that way than experimental features which benefit small factions of users.
NONE of those features seem like things mainstream users are likely to need other than simple easy to use versioning... if that's what snapshot would turn out to mean.