One feature which I think is mission-critical is the ability for Wrike to save and restore backups for users. I just ran into the issue where my main project plan templates became disorganized and it caused major, major amount of rework on my end as well as interruptions in my business.
It could also create a revenue stream for Wrike if you charged $100 to restore a session to a previous date. My hosting company does this and it's a major relief knowing the option exists.
One reason I went with Wrike was the layered sub-tasks, unfortunately whens something goes wrong (a task in a shared folder gets removed, parent task gets deleted but the sub-tasks remain) it causes MAJOR structural issues which is not easy to undo.
Think it's an obvious one and a win-win.