I think there may be a few too many Vogues already. They, of course, change as time goes by depending on the times and on the editors. Often, Vogues are good in the beginning and then they slack off. Like German Vogue was great in the early 80s but when downhill fast. But the worst Vogues I've ever seen were 70s Australian Vogues - they really were so bad one just wants to cry....
Anyway, I think that American Vogue could do with a revamp at this point. It's too perfectionistic and clinical - perhaps a more inspired typography would do them some good, or at least separate them clearly from their increasingly vile ads (Walmart...you know?!?). As far as celebs go - oh people loved their celebs back in the 70s as well, but they still didn't mess up the covers more than occasionally. I think the reason for celeb covers is that the publicity machine has changed somewhat. People don't know what they want - and they should be educated/inspired. as for its history - contrary to all the other editions, American Vogue has never been completely worthless, although 2002/3 was close to such a state.
British Vogue is one of the "youngest" Vogues - it has some good features, but it's not really in its haydays (amazing mags in the 60s though). At least they do have a sort of unity for their editorials.
Italian Vogue is obviously, since the 90s, Steven Meisel's playground and is very dependent on his inspiration of the moment. Before that Italian Vogue was great until 1982 or so and then took a terrible nosedive until Meisel saved it. Sometimes spot on, sometimes just kind of off, but always skilled of course. Photographically more consistent than British Vogue, but still a bit obscure.
Vogue Paris is IMO the best current flavor. It has a unique typography, great paper quality, unified editorials, great photography and presents some of Lindbergh's and Demarchelier's most inspired work ever. Even the ads appear to be thoughtfully selected and placed - and the last three issues have been pure pleasures. The covers are still their weak point, though. As for its history...the 70s were the best, just astonishing issues all through the 70s really, and then in the late 80s this gem of a magazine just became more boring than a phone book.....until it was revived in 2002 or so by Carine Roitfeld. A lot of people criticize her, but they must be in denial...
Vogue Nippon - exquisite paper quality and printing, experimental and attractive photography. Never a complete waste of money. The covers or often not so very intriguing, despite model presence, but nonetheless better than average.
German Vogue - was great during its first few years but have since slipped. It's not atrocious and better than most Elles, but at this point it's not too inspired.
Brazilian Vogue - has its moments but tends to be rather T&A oriented, no surprises there.
Vogue China - I liked the first few issues, but I was turned off by my most recent purchase which did not have very satisfactory binding. The cover came off immediately...
As for countries that should have Vogue issues? It might be interesting with a Persian version, or something along those lines. And sometime later an African version. I heard that there might be a Vogue India at some point?
What is happening! I feel....violated 
