Ayrton, I disagree, why would a plate help even any pressure on any surface other than the back of the body? at the working end of the screws ( the pointy end ) there is no plate, so therefore there are only four small spots on the back of the neck being pulled towards the body,
Theres a million other things in your signal path between the vibrating strings and the actual speaker, that to single out lack of a neckplate being the cause of bad tone or whatever is just crazy talk. And that goes for a million other things that people give credit to great tone, it's a whole bunch of a lot of things that make for good tone.
I believe that whatever you use to join the neck to the body, if it's tight and rigid enough there will be no loss of tone, You may as well ask warmoth to stop burning the logo into the neck and body pocket, theres a place where theres no wood to wood contact,
As for your old and new ibanez, you can't support your argument based on two different guitars from diferent era's, Go pull two identical guitars off the wall at guitar center and play them, they will be different
In fact, I have a guitar i just put together where I installed shims at the base of the neck to tilt the neck back, I am experimenting with a taller bridge.
I can see a gap between my neck and body. I could almost slide a thin dime in there. The guitar sounds awesome, plays solid, stays in tune etc...
you wouldnt know that gap was there if i didn't point it out.