I can appreciate the value of movement when being attaked. Although, in Uechiryu and some other Karate systems, it appears as though when things get heated up, we tend to exchange blows and take the attacking stand.
There is a point where defence becomes offence and we go in to close the distance looking for a in tight position and opportunity to strike, take down etc.
I had taken Aikido for a few years whereas
we blended with the attacking force and redirected it into a throw or lock. However, there was full body comittment from the uki and they did not "square off" as some of the Uechi practicioners do.
I believe that when one stands their ground as to pick their shots rather than attack, utilizing movement is much more difficult to do.
The old beginner "8 step" movement was about that. Although many dropped it from there training due to it's white belt level material. One can add much to the drill as to work those 8 positions you refer to.
When confronted by a tank like person, as yourself (smile) one surely needs to move "out" of the way !