Below is the tiddler I have created for that purpose.
Hope it may be of some help to you or anyone else.
\define sb(name) $:/core/ui/SideBar/$name$
\define msb(name) $:/core/ui/MoreSideBar/$name$
\define remove() +[!prefix[$:/]] $:/tags/UnusedSideBar $:/tags/ModifiedCoreSideBar
\define move-to(to) +[!prefix[$:/]] $:/tags/$to$SideBar $:/tags/ModifiedCoreSideBar
You can modify core Side Bar elements from here or restore them to default value.
! Installation
//The following action will modify core elements.//
<$button>
<$action-listops $tiddler=<<sb Open>> $tags=<<remove>>/>
<$action-listops $tiddler=<<sb Recent>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb All>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Missing>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Orphans>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Recent>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Shadows>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb System>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Tags>> $tags=<<remove>>/>
<$action-listops $tiddler=<<msb Drafts>> $tags=<<move-to Notes>>/>
<$action-listops $tiddler=<<sb Tools>> $tags=<<move-to Tools>>/>
<$action-listops $tiddler=<<msb Types>> $tags=<<move-to System>>/>
<$action-listops $tiddler=<<msb Plugins>> $tags=<<move-to System>>/>
<$action-listops $tiddler=<<msb Explorer>> $tags=<<move-to System>>/>
Remove or move Core Side Bar elements
</$button>
Currently removed or moved Core Side Bar elements:
<<<
<$list filter="[tag[$:/tags/ModifiedCoreSideBar]sort[title]]" template="$:/core/ui/ListItemTemplate"/>
<<<
! Restore default core elements
The following action is used to restore core elements. (This may be useful before upgrading.)
<$button>
<$list filter="[tag[$:/tags/ModifiedCoreSideBar]]">
<$action-deletetiddler $tiddler=<<currentTiddler>>/>
</$list>
Restore Core Side Bar elements
</$button>