Kemper could control Rig Manager

How could it?

No parameters are reflected by the app 'cause it's essentially a "preset" (Rig) manager. If one day it becomes an editor, then it surely would do this, but not today.

EDIT: I thought you were talking about FX slots in Browse mode; I realise now you're probably talking about Rig slots in Performance mode.

My answer would be the same 'though. For RM to reflect Rigs' being changed in slots, I assume you'd have to first save your changes on the Kemper. Because it's a preset manager, it can only deal with what's been saved in your unit; all temporary edits, until saved, reside in the edit buffer of the KPA and are therefore "in limbo" at that point.