nicer url's would be a plus, however it's not entirely even necessary. google does a good job following links on it's own and mod_rewrite only sweetens the job providing you know how to put up the proper regexp for it :P the only thing that needs to be added is a base location meta tag.
Given that Google is - and has been for a while - smart enough to deal with any nasty urls we throw at it, the reason I support the purty urls is purely from a usability perspective. I'd rather be presented with the link...
I instantly have a clue as to what it's about, especially if I've bookmarked half a dozen discussions, it jogs my memory.
Given that mark is completely rushed off his feet at the moment with a ton of other vanilla flavoured things, maybe someone well practised in mod_rewrite would care to take a stab at creating the appropriate rules, and searching through the source to document the required changes (for when urls are printed).
I could offer to do the second part, but have had no experience with the first yet (although I really need to do something about that ^^)
I'm not sure how the version-ing works, but I suspect it's done locally to Mark. If someone starts changing code and sending it in, it's likely to clash with other bug fixes...and thinking about it, it's only likely to be no more than 30 links or so, which Mark tells me have a parameter class, which makes them easy to change.