I don't think that it's dying but i will admit that the console hopping can get annoying as i have no money so i have missed out on some of the games but that's not a huge problem for me also i don't that that the storyline is too confusing because I get most of it and i haven't played some of the games
I would have to go for:-
-The Black Cauldron (it's my favorite Disney film, it's also based of welsh folk tales so that's a plus)
-Toy Story (Because it's such a classic)
-Monsters Inc. (Because it would be fun and I can imagine fighting Randal and The Heartless)
-Tangled (I haven't seen it but the way it sounds it would be such a good Kingdom Hearts world)
-Lilo and Stitch in Hawaii (Because fighting the cousins and The Heartless sounds very interesting)
My main favorite was Xemnas just because he had really quote-able lines and I loved the stoic-ness and the hand gestures. My second favorite was Axel because he was awesome and likeable and had fire powers. My third favorite was Zexion just because he was so mysterious
I've not managed to defeat Sephiroth in KH1 yet but i'm not amazing at that game but i have managed to beat him in KH2 which i did find slightly easy because the growth powers helped me a lot and i don't have final mix or BBS so i haven't fought Terra or the MF
I enjoyed using the skateboard a lot in this game, mainly for beating up heartless with it cause it's definitely something you don't see every day and also because it gets you place so much faster