From: Wizzup?
There was a thread on MITB about mouse movement, I think he's referring to that. However, I still doubt that Jagex tracks all your mouse movement AND send it to the server for processing. Perhaps they do client side processing.
Well, if you think it's not human like, try writing a function that, given a set of mouse movements + time, determines whether it is WindMouse or a human?
I've already thought of doing that, and may when I have the time. However, when you consider that a human can tell the difference with no difficulty it isn't necessary to write the program to demonstrate that. You can judge for yourself; here's output from a test program I wrote while working on mouse routines:
This is WindMouse:

This is me moving the mouse:

WindMouse shows a lack of understanding for (or analysis into) how humans actually move a mouse, and the whole concept of a global mouse function to satisfy all mouse movement is flawed in the first place, since humans make different types of movements depending on the task at hand. For example, the movements where you want to get to something far away in a static location (e.g. checking your stats), clicking on something where precision is not needed (e.g. your inventory items, which have an enormous hitbox), and clicking on something where precision is necessary (e.g. selecting an option from a right-click context menu) are very different. [There is also accidental mouse movement and idle mouse movement, which are not properly simulated either].
So, to recap, you need to support different types of mouse movements based on intent, precision, and distance involved.
I haven't looked at the WindMouse source, but honestly from the picture it seems as if it's just randomly picking a distance to skip between points while far away, and then slowing down to a crawl as it's right nearby [and of course, you mentioned the overshooting issue]. The shape of your curve is decent - the distribution of your points along it, however, is very inappropriate.