Thought I might offer an opinion. You could ask your question of Mrs. Birkenbihl as well.
You asked "Any thoughts on how they compare in this regard (from anyone)? Wouldn't the neuronal effects of Imagestreaming be more "random" than those of ABC Lists or auxiliaries? I'm sure it does create new connections through "pole-bridging," but since Imagestreaming is "uncontrolled" how are the benefits different?"
We believe that the anti-aging anti-alzheimer's effects of the ABC lists are a result of keeping neural pathways active. The analogy being that if a tree falls across a superhighway it will be less disruptive than if it falls across a footpath. Build neural superhighways and you also bathe the brain in the neurochemistry (master neuropeptide secretagogs) secreted by white brain cells that keep the grey matter active.
In addition, the gold bullion of autobiographical memory store can stand to be depleted even if the plaques associated with alzheimer's develop. Because you will have so much stored, you can afford to lose some.
Keep in mind that "pole bridging" is largely building connections across the corpus collosum. These connections help to hook up far regions of the brain not normally associated with conscious thinking tasks. Will that serve as anti-aging exercise? Perhaps, but maybe more because you are keeping the brain active in a problem solving mode. The ImageStreaming done for problem solving purposes may stimulate more regions than passive or uncontrolled ImageStreaming, but I don't know that.
You then asked:
"He says that only direct experience with feedback generates new brain growth. Does this contradict the Virtual Learning concept at all or are we saying that, since the brain can't tell what is imagined from reality, it really doesn't contradict. If the brain can't tell the difference, where is the feedback in the imagined learning?"
In fact it has been shown that mental image rehearsal can stimulate blood flow, muscle development, and trigger small muscle group entrainment. Far from mere passive observation of another, the person who uses Virtual Reality mental image rehearsal learning recieves an incalculable whole-body benefit.