Splitting this out as a separate feature request from Better UX for tree-like models as it’s a keener pain-point rather than merely a nice-to-have.
Currently the only way to modify position and parent is drag and drop, which is very cumbersome, especially if the parent I wish to use is currently very distant from the record I want to modify.
In manual-sort collections (not tree) you can set an explicit position value in the Info panel for a record.
I would like to be able to do the same in heirarchical collections: (a) set position with number and (b) set parent (click, record picker, choose parent).