Noooo. "save a copy" is a common option in a lot of apps. for saving backups without changing file names. I.e. your file might be massive_project.svg, and you can use "save a copy" to save massive_project_a.svg, massive_project_b.svg, massive_project_c.svg etc. while you're working in case something goes wrong or you come to regret a design decision. So it's not necessarily related to export at all. I'd say leave it in.
That makes sense, and it's not confusing if it just does a one-time save of the current file in it's current format (which, ideally, would be Inkscape SVG by default, with plain SVG and compressed SVG as alternates).
Well, assuming SVG is also available as export (which it probably should if it can give you the possibility, as with other formats, to export only a part of current drawing) you could just export your work regularly and the result would be the same.
But you have the added overhead to your workflow of defining variables in the export dialog. I frequently want to export certain sections/items of the svg repeatedly while also saving copies. I really see the value of having both, in particular if the "save copy" function has an autonumbering option.
One could also imagine that you want to make different types of exports, none of which are saves. Say, you are desinging a web site, and you need to export both as svg for the cool kids and png for the poor souls stuck with antedeluvian webbrowsers.
In such a case, it would be nice to be able to duplicate the export dialog, keep both copies open in the dock, and have the choice between several export buttons. One would then be able to name these instances of exports ("export targets").
Then there would be an export targets dialogs, where one could activate each target, or create new targets. On hitting Ctrl-E, all active targets would be exported. Maybe also make it possible to attribute shortcuts to each target.
Maybe each document could then come with a set of default targets, say "backup to svg", "layers as frames for animation", "each group as a pdf", "each group as a png", "page as pdf", "drawing as pdf", and so on... And also some constructors like "batch target from regexp", which would allow one to specify a regexp, and the target exports all groups whose name matches the regexp into a separate file.
Maybe also allow direct access to the export targets via a submenu.
This would of course prevent "save backup" and "export" to shadow each other: they would be different targets in your export submenu.
Hope it's clear, I really believe this interface would not be half as frightening as it looks, and it would really be powerful.
Florent