Figuring out dependencies for small projects is not hard. But once you start dealing with a dependency tree with hundreds of dependencies, things can easily get out of hand. (I'm speaking from experience here ...)
The other point is that if you use an IDE with incremental compilation and Maven support (like Eclipse + m2eclipse), then you should be able to set up edit/compile/hot deploy and test.
I personally don't do this because I've come to distrust this mode of development due to bad experiences in the past (pre Maven). Perhaps someone can comment on whether this actually works with Eclipse + m2eclipse.
