The sequencing programs have pre-determined what people will do. I'd go as far as to say the sequencing programs themselves are kinda composing the songs. It's like people doing the actual sequencing are just doing what the programs direct them to do. I don't know how else to put this...someone else could be more eloquent....but is the artist the tetris designer or the tetris player? This problem isn't exclusive to hip hop production...but it's certainly a good example of it.