EMC2 can work with named variables
e.g.:

#<_xoffset> = -0.28000
instead of
#100 = -0.28000

This was already mentioned here:
http://www.machsupport.com/forum/index.php/topic,18453.msg127162.html#msg127162
but doesn't seem to have a topic in feature-requests yet.

This for example completely prevents me from using the etch_z_adjust script for prototype PCB milling.
(adjusts the PCB2Gcode output to run a 10x10mm grid of Z-probes to determine the actual z location of a not perfectly even PCB suface)

What does your Gcode look like there may be a work around.  Mach3 has never exposed the internal parameters to Gcode and as it looks never will. Mach4 maybe.

Also Mach3 has never had conditional Gcode and never will. Mach4 maybe.

Just a thought , (;-) TP

User variables with human readable names, not internal variables of MACH3.
I only saw subroutine calls and looks, no conditions in the code.
Of cause that eould be really useful too. As long as it uses the same syntax and semantics as others.

The last reference to MACH4 I just saw was from 2010. Is that actually going to happen within our lifetime?

Never going to happen in Mach3 (;-)

The one thing about the  Gcode language is there are so many versions to choose from (NO known standard).

Just a thought, (;-)TP