Citizen Kane

What's the big deal with Citizen Kane? Maybe I missed the mark or am just not educated enough in the art of film, but I don't understand why Citizen Kane is "one of the greatest films to date" according to critics. I understand that "Rosebud" ends up being a big twist and Kane's life is explained (arguably) becaues of that one word, but a sled? Seriously Welles? My opinion on "Rosebud" is that it makes the movie very cheesy. It could've been "tulip" or "tiger lily," which would've made it even worse, but I feel like the ending was just a cop-out. Although the storyline is fairly two-dimensional, with flashbacks and montages and other unique ways of telling it, the ending just seems so flat. There is no big excitement or climax leading up to it. Kane gets abruptly taken away from his childhood, goes power-crazy, has an affair, blows his political career, forces his wife to flaunt her crappy operatic talents, his second wife leaves, and he dies saying "Rosebud." Is it really that exciting or original? I'm not saying the film completely sucked but it just seems so stupid. What person in their right mind would want to watch a movie that ends with a childhood sled as the thing that ties everything together? I need some excitement, maybe a bit of violence even. I'm in no way completely bashing the work Welles pulled off but could someone please explain to me why Citizen Kane is so amazing? Unfortunately "rosebud" wilted in my opinion.