Late response from my side,
I find it difficult to put into words, but perhaps its Seiko's design cues for the movement that I feel is underselling itself?
For instance, the hi-beat GS models I feel could be done more interestingly. The bridges all have no anglage at all - machined or not. While there is nothing wrong with this (it still has striping etc.), it does portray that sense you'd relate it to some of the other Seiko movements lower within the range.
The top plates/Rotors of the GS and Credor are attractively done - with very even (albeit deep) striping. What I feel could have been done differently is the bridges under (e.g. holding the Glide wheel, or the ratchet wheel). The finish I feel, could have been replaced with a more consistent brushed finish.
Meanwhile, for "high-end horology", screwhead finishing cues are usually observed by bevelling of the screws - which also exists within Swiss counterparts (e.g. Omega, JLC, ...)
Note the screws below. While they are not done as sharply as the highest end watchmakers (of course!), they provide a sense of detail - due to the sharly defined slots that are still "chamfered" to an extent throughout the slot, and the peripheral of the circle. It is totally unnecessary from a utility point of view, yet is an indication of artistic prowess by the brand for a luxury timepiece.
I'm highly nitpicking here - as I feel that some of the above could have been done with little extra cost to the production. However, I understand that it is (Grand) Seiko's ethos to provide a high-end product with exemplary finish all around, while still being a robust "tool"-ish utilitarian watch that could handle day-to-day activities.