This idea has been circling around my mind for a long time. Also some people here express similar notions to me, which feeds into that process as well. The idea is, what is the difference between visualizations and what we may call sensoria, which is the total character or gestalt of all the waking senses?
For one thing, unlike with Buddhism, we generally do not consider mind-sense to be a sense, and there are some good reasons for that. So we deal with the so-called 5 senses instead of 6. The reason for this is because we believe senses have to convey information from the "outside" as it were, and the mind-sense is thought to fail in that role, and so is not a "proper" sense by our convention.
There is another reason not to consider mind-sense to be a sense. And that is, mind-sense allows the duplication of all the other senses via visualization. So even as the "physical" eye is engaged, I may also see in my mind's eye an apple. Similarly I can experience visualized smells, touch, sound and other types of sensations all while being fully awake and alert. So when I speak of visualization I don't refer only to vision, but I refer to any what would be called "imaginary" sensing. This latter, so-called "imaginary" type of sensing is not dependent on the fleshy organs. Because the mind can duplicate all the conventional fleshy senses, it is obviously special and shouldn't be thrown in together with the rest as a "sense," imo. But insofar the mind, among other capacities, is also a ground of experience, it can resemble the senses while also being completely superior to them.
A big hang up for me tends to be a feeling that the conventional sensoria are just so damn impressive, so visceral, so shiny, so up in my face. So I was thinking, what about visualization?
What if I were to make my visualizations so stable, so bright, so detailed, that they were indistinguishable from conventional sensoria? I bet this would change my attitude toward the conventional sensoria. I already intellectually regard all that I experience as a dream. Being able to generate visualizations as shiny and as stable as what I experience conventionally would really up the ante, so to speak.
Another possibility is to try to dim and dissolve the conventional sensoria in order to bring it in line with the visualization, assuming that one doesn't experience impressive visualizations. I sometimes play with this approach as well, but this one is much more psychologically difficult because it involves in some sense dissolving what I am so desperately clinging to. It would be much more clever and subtle to avoid the process of sensoria dissolution and instead bring the visualization up to the level where it is in no way inferior to the conventional sensoria.
So developing visualization is probably as important as say lucid dreaming. When my dreams were able to duplicate the visceralness of the waking experience, this had a huge impact on my outlook. I bet a similar impact will result when my visualization hits the same level as the waking experience. Currently whatever I visualize tends to be somewhat dim, unstable, hard to see, lacking in details, etc. But the good news is that my visualization skill is workable, so I have something I can improve upon. It would be trivial to make an incremental improvement in my visualization skill, then assuming I was persistent, I could probably achieve a great change eventually.
At some point if I can make visualizations sufficiently stable and bright I can just up and start living inside of them and begin completely ignoring conventional sensoria. Some time later conventional sensoria will atrophy to the point of non-existence, and I'll be out of convention for good. Alternatively I can begin mixing visualized and conventional appearances into one seamless whole. Either way I would deconventionalize myself to some extent.