Click count is definitely a big drawback for me, especially in adding/creating relation.
If I didn’t misunderstand your approach, you are attempting to improve the flow and design for current relation menus. What do you think if we are to incorporate relation setting into search pane / command palette in the spirit of accessibility?
That way users don’t need to have additional thought needed to consider functions’ locations - relation pane or block button… However, adding too much to search pane might not be a clear approach 
(especially with me suggesting to incorporate flow view into search pane as well 
)