Fortunately, nobody else has machines like you, which need all of these advanced features that are required by only you.

And many of the features you mention are motion controller specific, and not necessarily native to Mach3. A default Mach3 install with a parallel port can't do most of what you mentioned.

Number of users is a meaningless stat. So what if more people are using an inferior product? How is that a benefit?
UCCNC is every bit as customizeable as Mach3, and is probably easier to customize. It also supports scaling. And afaik, doesn't suffer from the many bugs that Mach3 has when using offsets.