Hi Randy, a very reasonable question! Generally having the table set up this way, all else being equal, is much more rigid than having a moving gantry. You also don't have a stack up of the play in the axes. What I mean by this is if the gantry rails have some play, and then the X axis rails on top of that have some play, and then the Z axis rails have some play, by stacking them all on top of each other you compound the issues resulting from such movement. In this configuration only the Z axis is on top of the X, but the Y axis is independent.
It also allows for a much heavier duty gantry to be used without the penalty of having to move it with huge motors or slow speeds
The downside is the machine takes up a lot more room for the same size working area.
Yes, my replacement spindle cable arrived yesterday which is the proper multi strand flexible cable required.
Not sure what you mean by 3 wires - the spindle only has 3 wires for the input. Do you mean I should run an extra earth connection to the body of the spindle?
I don't see how any of the rest of the wiring is unsafe, a bit messy perhaps but it's all rated for the current required and the cables do not move within the cabinet. The body of the machine is earthed as well as every component within the cabinet.