Surely you understand that bumper movements are, by definition, obsolete, and that fact has nothing to do with the quality of any particular design. As for parts availability, what, exactly, does that have to do with design flaws? Parts availability for vintage watches depend on a variety of factors, and unless a design was so poor that production was quickly abandoned, eccentricities of design are not likely to be a major problem.
It seems that you are conflating an intrinsically limited design (i.e. Zenith had no option to produce a full-rotor automatic at that time), with more modern designs. To reasonably assess the quality of a bumper movement, one must first compare it to other calibers in the same category. So, for example, if you were to compare the 133.8 with, say, an Omega 351, you might be able to tell us what it is you prefer about the Omega design, and why.
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