The problem is, I got a little ahead of myself, and a little too excited when I was using a particular piece of bamboo, and I wanted to use as much of it as I could. That was a mistake. Here's the pipe in its original configuration:

The shank, while the right diameter, is too long. It could also be too short, if I had gone a different direction with the pipe overall, but in this form, for the pipe that was intended, it's simply the wrong piece of bamboo. The space between knuckles is too long, and there's no way to balance the length of shank/stem combo with itself AND balance that assemblage with the size of the bowl.
In the photo above I had already disassembled the pipe, and decided to fit it back together to share the experience. The blackening is from the micro-torch that I used to heat the joint. The piece of bamboo that will be used instead is just above the pipe.
Here is the pipe after putting the new bamboo shank on and fitting everything together.

Not only is the piece of bamboo shorter, but I also elected to use thinner transition pieces, which just look better. The other transition accents were too thick, and contributed in some degree to the feeling of the pipe being out of proportion. This new piece of bamboo has shorter space between knuckles, allowing the overall length of the shank to be much shorter.
I'm not prepared to have any real conversation on proportion, compositional balance, flow, or whatever else - I'll leave that to the critics. However, in this case I just knew that the pipe looked "all wrong". The bamboo was the right diameter for what I wanted, but other than that it fell far short of intent. I guess my point is to follow your gut in some cases, and work on developing an understanding of what looks right and what doesn't. Someone with an art background might be able to contribute something meaningful in artistic terms or the whys and wherefores of aesthetics - but for most of us it's simply about developing an understanding of what looks good, and what doesn't.
And also, if it doesn't look great, don't be afraid to rework it. Or scrap it entirely and start over.