You are absolutely correct about the negative feedback.
My fav mod has always been to disconnect any negative feedback from any amp I use. This will in many cases frees the amp up, and in some give a beautiful roaring overdrive when the power amp is cranked.
As for what you say about IK not divulging too much information, this is a pattern I see with many brands of products for guitarists, and the answer is this:
Most guitarists are ignorant, and dumb too. Not all of course, and obviously that is not your case. If you give them technical information, it will be classed as "gimmicks" (stupid people call "gimmicks" anything they don't understand).
Case in point, Bugera amps. It is the ONLY brand that offers the incredible Infinium tech, which you won't find in amps costing 6 times more. This is , I believe, Behringer's take at the TubeSync by Aston Electronics. Incredible stuff. Orange Amps used to sell something similar as a mod, which costed about 500 bucks, and you had to pay a tech to get it installed.
So Bugera offered this for basically FREE, really a killer feature in a tube amp. And what did they get? 85 per cent of guitarists bitching and moaning about it being all a "gimmick" and "hype".
I am not surprised Amplitube tries to "keep it simple"
. Most guitarists are simpletons, although, again, I am not speaking of all. And some are smart people, but they aren't the rule.