I think page, sortname and sortdir work better as query string values rather than path segments because 1) they’re all optional, and 2) their order doesn’t matter.
None of these are actual directories, thought, correct? There’s no such thing as finance/economy/index.php. But rather, finance/economy is itself the resource location. Keeping a trailing slash just for the illusion of a directory seems like unnecessary cruft to me.
Your rewrite would likely have to change. But it’ll probably work out better this way. You won’t have to worry about naming collisions between sort names such as “by-date” and article slugs.
Are you saying this for either #4 (my preference) or #5 (your preference)?
Or just for #5?
This whole thing has me freaked out and scared, but I want to push myself to think about things in different ways and come up with the best solution!
Looks like I have A LOT of work ahead of me rewriting all of my mod_rewrite and PHP code. (Such a bummer, because I was really proud of that mod_rewrite you helped me perfect!!) sigh