Nope, because you have to understand in depth the existing work in order to rewrite it properly. Then only good rewrite is when you understand the existing stuff enough to see what is wrong with it. You can't rewrite something if you don't know what it does.
If you don't understand it, how do you know what to write?
You know the know and understand the goals, but you don't understand the internals.
But look at the example cited: Google ended up with TWO systems, because he didn't fully understand what the program did.