(In reply to comment #1)
> Here is a page that has a table and a couple transcluded navigation-box
> templates at the bottom:
> [[List of countries by incarceration rate]]
> 
> With VisualEditor (VE) the table is editable and WYSIWYG.

(Yay. :-))

> But with VE the existing text in the 2 navigation boxes can not be edited as
> far as I can tell. At least not within VE from that page. I am talking about
> after clicking the edit icons for the navigation boxes.

Yes, VisualEditor is disabled for the Template namespace, and likely will be for a very long time (or forever). It's mostly used for very complicated transclusion wikicode which often can't be edited visually, because it doesn't form a complete document, only part of one.

> New parameters can be added to one of the templates, but not to the other. I
> don't see a way to edit the text for existing parameters in either navigation
> box. 

I'm a bit lost here - you mean parameters on [[List of countries by incarceration rate]]'s invocations of [[Template:Incarceration]] and [[Template:Law country lists]]? Those templates take no parameters, though it's possible to add new parameters to template invocations that don't currently have one - see my edit (actually two edits) with VisualEditor here: https://en.wikipedia.org/w/index.php?title=List_of_countries_by_incarceration_rate&diff=560637005&oldid=559696805

> So to be able to edit one of those templates in source mode or otherwise it
> would be helpful to have a direct link to the transcluded template page, and
> not to the many templates that make up such a navigation box at the core
> level. 

You can definitely edit those templates in source mode still - do you mean, edit the invocation of those templates? You should be able to replicate anything you can do with a template invocation in source mode using VisualEditor at this point. On the other hand, trying to offer "edit the source of this template invocation" is extremely technically hard (as well as being a very complicated user interface issue for users).

> See related bug 878.

I'm afraid I don't see how that bug, about the wikitext editor's additional listing of templates used on section editing, is related. Could you explain the link?

I also don't see how this relates to this bug, which is a minor enhancement request to add a link to the used template on the template's pane (which I think is fine, but we'll have to work out if we can do this in all situations - what do we do when the "template" you're using is in fact a parser function? - etc.).