All good points, greenboy. I just like the independence I have. If a system goes down, I have a backup instantly. I also like being able to make on-the-fly tweaks to either system. I may call up my slap patch on my V-Bass, but not feel like there's enough mids or maybe too much. Maybe just a hair...but I'm picky that way. Sure, I can tweak the V-Bass, which involves stopping playing (at least with my right hand) while I push the edit button, go into the EQ parameters (either at the root level or the effect level) decide which parameter to tweak, grab the value knob (you know the drill)....
Or, I can just reach around to my Fishman (which is at waist level) and grab a slider and make an adjustment in seconds.
I'm not suggesting that I can't achieve good results with what you are talking about, but I've tried it both ways (a guitar player buddy of mine has as well...he notices a difference plugging his mags into the VG88 input as well, but he doesn't mind the difference....the GK input impedance is 1 Meg Ohm, btw), and while it's fine going through the GK input, it sounds better the way I am using it...to me anyway.
It's not an issue of being able to make it work...I understand there are many ways that will "work", but I want the setup that will sound the best for me.
I appreciate the input tho.