3.) Mostly because a servo system is more expensive and these machines are doing fine with 570oz steppers. As the machine grows so does the cuts it can take and the forces involved and past a certain point it gets hard to find steppers that match. Still Tormach is a successful platform based on steppers in the size range of the RF's so servos are not a requirement.
4.) Handles seem a little odd to me now. With ball screws it is entirely possible to push the table and back drive the handle. That's not so good. It means the tool can push the work around and if you aren't holding against it breaks or ruins stuff.
There is also the issue of an unbalanced mass rotating at a rapid clip, all it can do is add vibration which isn't desirable not to mention getting thwacked by that at speed is not going to feel good, especially where the Y motor sits on the 0704.
Finally you have to remember that a motor is a generator in reverse. If I grab the handle and really give a fast cranking to it you will find a substantial voltage being produced on the leads. That's not great either when the drivers are powered down. You are forcing voltage back at it from the wrong direction. I also notice a lot of BP's kept the handles but I can't say why its so common there.