Is there any technical reason you have the neck so deep in the body since you don't really have access those upper frets.
I could say that there is a greater intramolecular vibrational energy redistribution resulting in enhanced tone (magic sauce), but that would be insulting to the audience here, and I would NEVER espouse this.

<<My first cup of coffee just kicked in, can ya tell?>>
In reality, this has been an evolution for my recent builds. I'm thinking a neck with more mass could potentially be more stable. Note that I am making the neck thicker as well. So far so good. For the few builds I have completed, I have yet to have to adjust the truss rod due to seasonal changes. Two of the basses are almost 2 years old, the other is only about 6 months.
Also, I think that the traditional Fender style pocket is a bit flimsy and could potentially be made more stable by putting the heal deeper into the body and using 2 extra screws to secure it to the body. Along with making the neck pocket deeper and longer, I making them so that they are what's called a transitional fit, and almost to the point where it is an interference fit. My experience is that instruments with tight neck joints just plain over all feel better.
What I am doing here is nothing new. For those of you that remember SD Curlee, this is what they did. They added mass and contact area to the neck. The neck actually ran almost the entire length of the instrument. I don't know the technical drivers behind their rationale, but my perception is that it is a very solid feeling instrument.
Another driver to my design is that I can. Everybody, and their brothers uncle do Fender clones just like a Fender. Time for a little change. Explore new worlds so to speak.
So there you have it