WTF? What's an "internal insulator"?
The antenna problem is very simple -- touching both antennas over the dielectric gap result in signal attenuation due to a detuning (change in effective inductance) of the antenna. I don't care what kind of "insulator" they put in phone, it won't make any difference. The only solution is to insulate the metal antenna from touch by hiding it internally or coating it with a non-conductive coating that prevents anything conductive (fingers, metal, whatever) from detuning the antenna. Very simple Magnetism 101 stuff.
Frankly, I'm surprised that the analysts haven't caught on to this yet, but they continue to spew all sorts of pseudo-science postulations about how to fix this problem.
BTW, an in-store fix is relatively simple -- just tear the phone down and replace the original antenna with the non-conductive coating version. 10 mins max, though your wait times will vary.