Honestly, I see this as a mod supplied by a third party; like
vBSEO does for vBulletin. There is just so much that can be done it could support an entire product all on it's own.
As far as I know, we are the only gallery to offer two sets of URLs throughout its product to support
SEO and "regular" URLs; in my mind, that is enough right that.
In fact, many URLs could be modified within the construct url function in pp-inc.php to include titles or whatever.
That's not to say we wouldn't consider ways of making it better (always am); but this kind of granular
SEO work would most likely fall into an add-on kind of product for PhotoPost.