Make TargetVelocity more user friendly

[Morgul]

Currently, TargetVelocity is rather obtuse. The problem is that while we have a lot of possible parameters to play with, what they each do, exactly, isn't clear.

So, what we need is to both improve the documentation of these parameters, as well as rethink that section of the API. Perhaps there are some improvements we can make that will give the user more intuitive parameters to tweak, while still keeping the flexibility of the current system.

Mostly, this is an issue attempting to open a discussion, and from that (hopefully) a plan.

@whitelynx, @Burstaholic, please weight in.