Yea, they lied to you. Ford has torque management, as does GM. People want a smooth driving truck with ridiculous amounts of torque for the lowest possible price. You can't have all 3. The reality is that most people don't need the torque,they just like to be able to say that their truck has more torque then your truck. Its all childish, really.
Ram wants to build a truck that people aren't crying about it shifting hard and it costs too much money. The result is excessive torque management in lower gears to allow for smooth shifting in a reasonably affordable price point. Did the truck drive like that when you took your test drive? If so, then you knew what to expect. If you didn't test drive it... not sure you have much ground upon which to stand.
I have noticed that I can get my 68RFE to give me dead pedal if I mash on the accelerator, take my foot off and then mash it again. I've never experienced the dead pedal in any other circumstances in 15K miles of driving it. I'm not sure why it would be different on the Aisin, but it sounds like it might be.
By the way... did you really pay $11,600 for a Cummins/Aisin? I highly doubt that, *** that is MSRP for them. It seems a little advantageous to quote MSRP on Ram and more of an out the door price for GM and Ford. I get that you aren't happy and are trying to justify your position though...