Maya Fur is kinda hard to get rid of because the control system for it is really nice. Many packages rely on the maya fur system to control their fur(MTOR, plus many in house tools).
You can buy both of them as separate options, thats why there is unlimited and complete. I don't see the big deal, I would rather have the choice. Syflex with XSI is 9k, Maya complete with syflex is only 4k. Shave is only another 1k for maya.
Not sure why you would want Havok over maya's internal dynamics. While it is a nice dynamics engine, maya's built in dynamics covers a much wider variety of things. How many people do you know that use Reactor over Maya for dynamics?