For the record, I've never used a GCX before...So this is my first rodeo with one.
For someone that's going to run a series of loops together, having some internal jumpers/switches to jump loop 1 to loop 2 etc, sure would be nice.
(warning, below content I'm sure will invalidate any warranty)
This looks easy enough to "mod" into a GCX. If you crack the GCX open, you can jump the tip and sleeve from loop 1 out to loop2 in etc. About 12" of bus wire and you've jumped 1-4, and 5-8. You'll only need a patch cable from 4 out to 5 in.
Jumpers wouldn't be costly to add, but the PCB and production redesign to accommodate would be. Switches would obviously be more costly than jumpers.
Also, while not necessarily detrimental, running a series of loops to select a drive in front of an amp could be seen as a "bad" thing. Having a product that was more of a "selector" (parallel switches with only one active option) as opposed to a series of loops might be seen as sonically more "pure." At least more direct.
In my intended application, I'll have 6 switchable drives in front of an amp. If I used the patch cables externally for out to in, that's about 15, 1/4" connectors and approximately 5 feet of extra cable to run through. Granted, the buffer helps significantly, but this is still a bit of an issue for OCD "purists."