I actually like the white things in the middle, they remind me of spider mums, and your use of the maple-leaf brush on vectors is nice and subtle.
On vector art . . . what is it that you want to do with vector art? Vector art can do practically everything that any other art medium can do, simple or complex. For example, you can go see various levels of complexity in my gallery: Mermaid is vector, and people have said it would make a good book illustration. Shattered Autumn is also vector, and it's just two colors and black on white. Another vector artist to see is :avatar ekster: very good attention to detail, I like the plane one and the wind pic, they're both in my favorites.
So . . . what did you want help on, when it comes to vectors? Pen tool? gradients? patterns? My best suggestion would be too fool around with the program and come up with what you like. Because different people have done different things with vectors. One last example: the map in my gallery was made in a vector program. In fact, that's how I first got involved in vector art programs.
the center line doesnt work too well. it blends too much with the white curved things in the center abd everything gets a bit jumbled. maybe change that line to a brown halftone so it does not get confused with the rest of the piece.
i really like how the curved things break up the area in this. they work really well but might look a bit better if the were off center.