consumer standpoint) the more I am increasingly conflicted - I both agree with you, and disagree with you.
You and I both know just how finicky and how much unknown "black magic" there is in these things - a piece runs with a stable beat and solid in all positions, only to suddenly, without apparent reason, go wacky, either on the wrist or on a winder. Yet, a week later, it settles back down and works reliably for another several years.
Or the 7750's that just won't work right, even though the fundamental design is robust and quite accurate.
etc etc etc.
But on the other hand, these "miracles of complication" generalizations that you and I have bandied about, which can be traced back to Walt and of course before, more often than not lead the casual reader or those with less broad exposure to these things take these comments too literally, and perhaps conclude these things are either too sensitive, or over estimate the miracle that these things work at all.
The basic concepts and engineering actually aren't that complicated - basically, a hammer strikes a gong, much like a fork or spoon striking a lead crystal goblet, with the resulting vibrational energy producing acoustic "tings" or "tangs"
The system itself adds some complexity and of course influences the qualities of the tones produced (including the volume, of course) but overall, the basic function of producing tones ain't that "miraculous."
The "draw" of the hammer, as well as the recoil of the hammers after the strike;
the actual force with which the hammers strike - a functional sub-system, actually; and where they strike, on the gongs;
whether the coils are drawn as one unit from the block or soldered on;
how the metals (both gongs and hammers) are alloyed and worked - this area of repeater design and execution is where the "romantic" story of the use of equine urine from virgin mares used to "temper" the gongs comes from - don't laugh, readers, there might be some truth to this, though it is usually presented mostly tongue in cheek - how? Most likely uric acid...;
how the movement interacts with the resulting waveforms; how the case amplifies or dampens the sounds; whether the case is on the wrist (usually dampening) or pressed against a piece of paper, to act as a membrane amplifier; how long the gong is (being round, how many times it goes around the movement) and how thick and where - hence, the practice of "tuning" the pitch of the gongs by removing metal from the gongs, usually from the area near where the gong attaches (or emanates from) the block;
all of these ways to tune and adjust repeaters are well known and reliable in that they do influence the sound and/or volume, though exactly how is still not completely known - a sort of "Unified Theory" of repeater design, execution, and tuning is missing.
Scientific methodology usually works from a "ceteribus paribus" approach - identify variables, try to control as many of them as possible, and isolate and vary one to see how the tone and pitch are effected.
The problem is, I suspect, the final sound quality of any repeater is an inextricable result of the whole - the movement, case, dial, rest of the movement, etc etc etc.
So studying ceteribus partibus sub-systems of meterials and adjustments and set ups might end up being more misleading than helpful, as a general theoretical foundation, because it cannot take into account the systemic, secondary, tertiary, etc levels of interaction between the various variable.
Put simply, just because using a stiffer, lighter case material results in louder "sound" for one repeater, may not be the case for another.
I realize strict scientific rationalists will have a field day shooting down my "points" and I have to resort to specific examples.
(gotta run, more later, but bottom line is, getting a consistently great sound and volume IS very difficult and more unpredictable than reliable, even if getting something to work at all, to produce SOME sound, is not all that difficult)