Hi Elijah,
That is only used when a page has no content at all, and it would seem very unusual to put the first/main content of a page anywhere except the middle panel so from my point of view it seems like it would just add something unnecessary there and it is more user friendly to keep it simple and not show unnecessary things.
Even if we implement an option to show the panel list dropdown I would make it not show it by default. I'm not opposed to making it possible if you really need it though, just trying to understand why you want that.
Best,
Joe