I suggest to add a new sort order: ‘By number of (linked) mentions’. This is needed to keep all the MOC/TOC notes on the top of the others. Currently user is forced to prepend underscore (_) or some number (000) to make these notes to be available on the top. Here is a similar suggestion.
_
000
Looks like currently you can ‘Star’ your MOCs/TOCs to make them available in a separate pane. But being able to sort by number of mentions is still a welcome addition.