-When I said that the movie was slow, I meant that the shot length is generally significantly longer than the shots of today's movies, which makes it seem slower in this generation of ADD editing. The actual scenes themselves all go on for the appropriate length of time and are all integral to it; it's the sort of film that can really have nothing removed without its entirety being compromised (though as I have said, I agree with Welles that Rosebud is actually the film's weak spot and that it should not have made the final cut).
-The very things that you say are NOT striking are exactly what make the film striking, in my opinion, but then again, I think that writing in modern cinema has taken a sharp nosedive, outside of a select few. The writing in the movie is absolutely pitch perfect. The dialogue lets us see into these characters very deeply precisely BECAUSE it's kept to the point, as action is a far more potent means of character development than dialogue; the movie is about penetration and trespassing, so listening to these people spill their guts about philosophy and such would just get in the way. 'Wittiness' is a rather vague term, but I would argue that this scene:
http://www.youtube.com/watch?v=_zKcddU8HKk has more wit and inspiration than just about any movie written today; it's only two minutes of the movie, but it says so much and has so many memorable lines, my favorite being, "You buy a bag of peanuts in this town, you get a song written about you!" which is simultaneously witty and probing, as it tells us so much of how Kane sees the world.
-I don't know what film you were watching, but I would argue that the things Kane does are EXACTLY as horrible as the people telling the stories say; they're not melodramatic and over-the-top, but they are certainly horrible. Hell, he fucking drags his untalented wife across the country and forces her to humiliate herself in front of audiences across the country just to prove to the world that she was not his booty call; tell me that that's not dark and grim. Hell, that's what makes Kane such an interesting character: he does so many horrible things but balances them out with moments of real nobility.
-I'm not sure how it's lacking in depth; it's been analyzed for 70 years, and people are STILL writing new things about it. If that's not depth, I don't know what is. I would argue that the film IS depth itself; it lives in a gray area and doesn't give us much in the way of black/white or right/wrong, which is what makes it so interesting, even 70 years later. Times change, but people don't.
-The cinematography is AMAZING and is some of the best of all time. Kubrick ALSO had great cinematography, but that does not diminish Kane's accomplishment in this area. Plus, directing was NOT in its infancy at that point; there was a rich history of directors from the silent and early sound era from which Welles drew, and he proved with this one film that he should stand tall as one of cinema's great artists. Look at how well the film's technical choices serve its artistic ambitions; that is directing at its finest, regardless of era. Hell, Welles did such a good job with this film that he never got another shot to repeat his success; as Ebert says, "Orson Welles made the greatest film of all time and was never forgiven for it."
-Really, I guess we should agree to disagree, but if you think that the average year produces even one film of the quality of Citizen Kane, we are just working from different axioms. There are, at most, only a handful of films throughout the history of cinema that are greater than Kane, and there is only one from this past decade that I would put ahead of it.
-In short: great art is not like technology. Advances do not lessen great art of the past. Kane is the sort of art, like the Mona Lisa, that will be studied indefinitely because it is so true to human nature and experience that it is timeless.
Edit: And Quentin Tarantino has not written ANYTHING close to the level of Kane. Writing for film is not only about dialogue; it's as much as about what isn't said as it is about what is said, and while Tarantino certainly writes great dialogue, his films do not have anywhere near the depth or sophistication of Kane's script. And I LOVE Tarantino.