Idea Summary
When you want to use LOV that return additional columns, you must use them in Shared Components, per documentation:

"Note: When defining a Popup LOV item type, if you would like to display multiple columns in the popup, you must instead define your List of Values in Shared Components, with the required additional metadata. Inline list of values can only be used to display single columns for Popup LOVs"
 

This results in LOVS being created in Shared Components that only one page needs. 

Idea is to move the creation of LOVS to entirely new component.

Use Case
Currently you are forced to use Share Components for a Pop Up LOV that returns additional columns, even if this is only needed for one page. 

Changing to new component will allow better control of LOV distributions and creation of truly application wide LOVS, that are not corrupted in future by page level items being added to them.
There will also be some benefit in reporting on metadata distribution of LOVS, which you can do now indirectly, but this would be easier to query such as "select all page level LOVs"

Preferred Solution
A new component to create LOVS and in that component you configure the LOV to be either application level or page level. The spot in designer for LOV creation, maybe that is a drawer or modal window that goes to this new LOV component creation page.

• For page level, you list this page(s) and only the session state from those page(s) are available to the LOV.
   
• For application level, maybe you can't even refer to page level session items, only global items, or there is a configure option to allow that. For example application global only / application global and page items.